Natural Resources Class 9 Notes CBSE Science Chapter 14 (Free PDF Download)

Natural Resources:

Materials given commonly on earth that can be utilized by living creatures are named to be regular assets. These are the land, the water and the air. The strong peripheral layer of the world's hull is known as the lithosphere. The water that is found on the world's surface, as groundwater, is known as the hydrosphere. The air that covers the entire Earth like a sweeping is known as the air. The district on earth involving both biotic and abiotic segments is called the biosphere.

The Breath Of Life: Air:

Air is a combination of gases like nitrogen, oxygen, carbon dioxide and water fumes. Nitrogen is utilized to create various natural atoms like proteins. Nitrogen is fixed in plants and is moved to creatures through natural way of life. Oxygen is utilized by plants and creatures during the time spent breathing. The burning of non-renewable energy sources likewise requires oxygen. Carbon dioxide is utilized by plants during the time spent photosynthesis. Numerous marine creatures use carbonates broken down in ocean water to make their shells.

• The role of the atmosphere in climate control – Atmosphere covers the Earth like a blanket. It prevents the sudden increase of temperature due to sun in the day and also prevents the steady escape of heat from Earth to outer space. The absence of atmosphere on the moon makes the temperature vary from $-{{190}^{\circ }}C$ to ${{110}^{\circ }}C$.

• The movement of air: winds - During the day, the air above the land in coastal locations heats up more quickly and rises. As the air rises, a region of low-pressure forms, and air from the sea moves into it. Winds are created by the movement of air from one place to another. The wind would be blowing from the sea to the land during the day. Because soil cools faster than water, the air above the ground cools faster at night.

• Rain - During the day, water bodies heat up and evaporate into the atmosphere. The vapour cools as it rises. The vapour condenses into small water droplets, which fall as rain as a result of the precipitation process. The prevailing wind patterns determine rainfall patterns. 

• Air pollution - Air pollution is the contamination of the air with chemicals, smoke, dust particles, and disease-causing agents. When fossil fuels are burned, distinct nitrogen and sulphur oxides are produced, which dissolve in rain and cause acid rain. The amount of hydrocarbons produced by the combustion of fossil fuels likewise grows. When there are large levels of pollutants present, visibility is reduced. Breathing air contaminated with any of these pollutants on a regular basis raises the risk of allergies, cancer, and heart disease.

Water: A Wonder Liquid:

Water can be found on the surface of the Earth, underground, and as water vapour in the atmosphere. The maximum amount of water available is salty marine water. The majority of the freshwater on the planet is in the form of frozen ice. Water is necessary for plant and animal survival because cellular functions take place in a water media. Dissolved substances are transferred from one portion of the body to another. As a result, in order to survive, organisms must maintain the level of water bodies. The amount of water available determines not just the number of individuals of each species that can survive in a given area, but also the diversity of life there.

• Water pollution - Water pollution is defined as the introduction of undesired elements into bodies of water. Fertilizers, pesticides, sewage, chemicals, and detergents are examples of undesirable substances. The amount of dissolved oxygen reduces when the temperature of the water rises owing to pollution. Aquatic creatures get their oxygen from dissolved oxygen. Many aquatic organisms die when the amount of dissolved oxygen in the water is reduced.

Mineral Riches In The Soil:

Another vital natural resource that sustains life is soil. Soil is made up of particles of soil, humus, and living creatures. In between the soil particles, there is also some water in the form of droplets or air. The soil is made up of the sun, water, wind, and living beings. Uneven rock contraction and expansion splits and breaks them down into smaller soil particles. Frozen water lodged in rock fractures and breaks the boulders, turning them into soil. Lichens that grow on the surface of rocks emit chemicals that break down the rocks and turn them into soil. River water breaks down hard rocks into soil particles. Rocks are eroded and sand particles are carried by strong winds.

Humus is a type of soil that contains pieces of decomposed biological creatures. Because it causes the soil to become more porous and allows water and air to permeate deep underground, it is a crucial element in determining the soil structure. The topsoil is the soil's top layer, which contains humus and live creatures in addition to the soil particles.

• Soil pollution - Soil contamination is the addition of pollutants that have a negative impact on soil fertility. The usage of fertilisers resulted in the extinction of many beneficial microorganisms and a reduction in soil fertility. Deforestation has resulted in the erosion of the soil's top most productive layer. Soil erosion was also caused by animal overgrazing. Wind and water can also carry fine soil particles away.

Biogeochemical Cycles:

The transfer of matter and energy between the biotic and abiotic components of the biosphere takes place constantly and thus makes the ecosystem dynamic but stable. These transfers take place through various cycles explained below.

• Water Cycle:

The entire method wherein water evaporates and falls at the land as rain and later flows again into the ocean thru rivers is called the water cycle. Water is able to dissolve a big variety of substances. As water flows via or over rocks containing soluble minerals a number of them get dissolved withinside the water. Thus, rivers deliver many vitamins from the land to the ocean, and those are utilized by marine organisms. A diagrammatic representation has been shown below.

• Nitrogen Cycle:

The nitrogen cycle is the method through which nitrogen is transformed among its diverse chemical forms. This transformation may be finished via each organic and bodily technique. Important techniques withinside the nitrogen cycle encompass fixation, ammonification, nitrification, and denitrification. Nitrogen makes up to seventy-eight percentage of the earth’s environment. 

The percentage of nitrogen withinside the environment is maintained through the nitrogen cycle. Plants and animals can't make use of atmospheric nitrogen quite simply. It must be constant via way of means of a few organisms referred to as nitrogen fixers. Nitrogen-solving microorganisms like Rhizobium stays in symbiotic affiliation withinside the root nodules of sure leguminous plants. These microorganisms convert atmospheric nitrogen into ammonia, which is applied quite simply via way of means of plants. 

Nitrogen-solving microorganisms alongside unfastened residing microorganisms withinside the soil gain ninety percentage of nitrogen fixation. During lightening, the excessive temperatures and pressures created withinside the air convert nitrogen into oxides of nitrogen. These oxides dissolve in water to offer nitric and nitrous acids and fall on land at the side of rain. 

Plants convert those nitrates and nitrites into amino acids. Ammonification is the technique with the aid of which soil microorganisms decompose useless natural dependents and launch ammonia into the soil. Nitrification is the technique with the aid of using which ammonia is transformed into nitrites and nitrates. Denitrification is the technique with the aid of using which nitrates are transformed into atmospheric nitrogen. A diagrammatic representation has been shown below.

• Carbon Cycle:

Carbon takes place withinside the elemental shape as diamonds and graphite. The carbon cycle begins off evolved in plants. Plants use carbon dioxide withinside the ecosystem to synthesize glucose withinside the presence of daylight via means of the procedure of photosynthesis. 

Living matters ruin those glucose molecules to supply strength and launch carbon dioxide via respiration. The burning of fuels for numerous wishes like heating, cooking, transportation and commercial strategies provides carbon dioxide to the ecosystem. A diagrammatic representation has been shown below.

• Oxygen Cycle:

Oxygen from the environment is used up in 3 processes, particularly combustion, respiratory and withinside the formation of oxides of nitrogen. Oxygen is lower back to the environment in best one predominant procedure this is photosynthesis. A diagrammatic representation has been shown below.

The Greenhouse Effect:

Some gases save you from the break out of warmth from the earth. A boom in the proportion of such gases withinside the environment could cause the common temperatures to boom globally and that is referred to as the inexperienced residence effect. CO2 is one of the inexperienced residence gases. A boom withinside the CO2 content material withinside the environment could cause extra warmth to be retained with the aid of using the environment and result in worldwide warming.

Ozone layer:

The ozone layer is found in the stratosphere, one of the layers of the atmosphere. Each molecule of ozone is made from 3 oxygen atoms. It is toxic however it prevents dangerous radiations from accomplishing on the earth’s surface, wherein they'll harm many lifestyles. Chlorofluorocarbon compounds (CFCs) outcomes withinside the depletion of the ozone layer.

Chapter 14 Science Class 9 Notes: A Brief Overview

The main topics included in the natural resource Chapter 14 Class 9 notes are rain, water and its pollution, Greenhouse effect, Biogeochemical cycles, Ozone layer and its depletion. In the following Natural Resources Class 9 Notes, let us gain knowledge about rain and its formation.

Rain

As you will see in Class 9th Science Chapter 14 notes, the evaporation and condensation of water are called rain. It is caused by the water cycle.

Acid Rain

Class 9 Ch 14 Science notes tell us about the formation of acid rain. Acid rain is produced by the release of various gases such as S02 and N02 which is released from fuels and vehicles. They dissolve in rain and form sulphuric and nitric acid.

Water

The Class 9th Natural Resources notes also give us a lesson about water. Water is one of the renewable resources. It is very important for the physiological activities of animals and plants. It is presented in two forms which are surface water and groundwater.

Class 9th Chapter 14 Science Notes: Water Pollution

A change in the biological, chemical and physical properties of water which affects aquatic lives and also makes the water unfit for use or consumption is called water pollution. The main causes of water pollution are:

• Removing desirable substances such as oxygen from water.

• A water temperature change.

Ch 14 Science Class 9 notes have the details of water pollution explained for you along with proper illustrations.

Notes of Ch 14 Science Class 9: Greenhouse Effect

Greenhouse gases like methane, carbon dioxide and nitrogen oxide are present in the atmosphere to stop the heat falling on the Earth and not absorb it. Hence, this keeps it warm and this phenomenon is called the greenhouse effect. That is how Science Class 9 Chapter 14 notes help you to get to know the meaning of the greenhouse effect.

Ozone Layer

The notes of Chapter 14 Class 9 Science tell us that there are three molecules of oxygen that form ozone and hence form a layer in the stratosphere. It also acts as a protective shield and prevents harmful radiations that try to reach the earth. CFCs react with ozone and break ozone which is known as ozone depletion.

Class 9 Ch 14 Science Notes: Biogeochemical Cycles 

An interaction between the abiotic and biotic components of biosphere make a system and such flows result in the formation of a cycle which is called a biogeochemical cycle.

Some Of The Cycles Are Mentioned In The Ch 14 Class 9 Science Notes Are:

1. Water Cycle

Water-cycle is the process by which water evaporates and as a result, falls on the land as water. The rain flows back to sea with the help of rivers and such a cycle is called the water cycle. The steps included in the water cycle are:

• Evaporation

• Transpiration

• Respiration 

• Precipitation

2. Nitrogen Cycle

The process by which nitrogen passes from the atmosphere to organisms and soil and returns back into the atmosphere is known as the nitrogen cycle. The processes included in the nitrogen cycle are:

• Nitrogen Fixation

• Nitrification

• Ammonification

• Denitrification

3. Carbon Cycle

The process in which carbon moves from the atmosphere to earth is called the carbon cycle. The processes involved in the carbon cycle are:

• Photosynthesis 

• Respiration

• Decomposition

• Combustion

4. Oxygen Cycle

The process by which oxygen is released in the atmosphere, and carbon dioxide is taken in by the plants from the atmosphere is called the oxygen cycle. Oxygen cycle includes:

• Respiration

• Combustion

• Photosynthesis

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