Natural Resources Class 9 Notes

Natural Resources is one of the most important and exciting chapters in Class 9 Science. A source or supply from which advantage or benefit is created, and it provides some utility. Resources can be classified as Manmade and Natural Resources. Resources which exist in Nature without the intervention of humans are called Natural Resources. Existence of humans and animals depends upon Natural Resources. Example: Sunlight, Water, Land, etc. This blog will help you find complete natural resources class 9 notes.

Air as a Natural Resource

Air, including nitrogen, oxygen , carbon dioxide and water vapour, is a mixture of several gases. It is important to remember that even air composition is the product of life on Earth. The main component of the atmosphere is found to be carbon dioxide on planets such as Venus and Mars, where no life is known to exist.

To break down glucose molecules and get energy for their activities, eukaryotic cells and many prokaryotic cells need oxygen. This results in emissions of Carbon Dioxide. Combustion is another method that results in oxygen consumption and the corresponding output of carbon dioxide. This involves not just human activities that burn fuel in order to get energy, but forest fires as well. Nevertheless, the proportion of carbon dioxide in our atmosphere is a mere fraction of a percent because carbon dioxide is ‘locked’ in two ways which is: 

(i) In the presence of sunlight, green plants turn carbon dioxide into glucose
(ii) Many marine organisms use carbonates which are soluble in sea-water to create their shells

The Wonder Liquid: Water

Another topic in our natural resources class 9 notes is water. Water covers a very wide area of the surface of the Earth and is present underground as well. In the form of water vapour in the atmosphere, some amounts of water exist. In the lakes and oceans, much of the water on the surface of the planet is located which is saline. Fresh water is located frozen at the two poles and on snow-covered mountains in the ice-caps. The availability of water varies from one place to another. 

Most countries have to struggle with a lack of water almost every summer. And in rural areas where facilities for the supply of water have not been implemented, people are forced to spend substantial time collecting water from distant sources.

In a water medium, all cellular processes exist. All the changes that take place between compounds that are dissolved in water within our body and within the cells occur. Also, substances are passed in a dissolved form from one part of the body to the other. Therefore, in order to remain alive, species need to maintain the level of water within their bodies.

Different Spheres Of Earth

• Atmosphere: The layer of Air covering the earth is called the Atmosphere. It works like a protective blanket for the earth to maintain temperature conditions. It contains gases like Oxygen, Nitrogen, Carbon Dioxide, etc. To know more about it, read our blog on Layers of Atmosphere. 

• Hydrosphere: Only 25% of Earth’s Surface is land; water bodies or Hydrosphere covers the rest 75%. All water bodies together comprise the Hydrosphere, and it is a necessary component for the survival of life on Earth.

• Lithosphere: The outermost and uppermost crust of the earth is called the Lithosphere. It is home to several kinds of minerals, vitamins, plants, soil, etc. 

• Biosphere: Survival of life on Earth is possible due to 3 major components: land, water, and Air that is the Lithosphere, Hydrosphere, and Atmosphere. The point where all these spheres intersect and interact is called the Biosphere. This is the life-supporting zone of the Earth.

Soil and Its Types as a Natural Resource

• The uppermost layer of the earth, also called crust contains different minerals that can help in sustaining life on earth. Still, these minerals are generally bounded in hilly areas and mountains.
• Soil is formed by enduring rocks through a prolonged process. It is home to plants, microorganisms, nutrients, etc.
• Types of Soil includes Sandy soil, Loam Soil, Clay Soil, Black soil, Red soil, Alluvial soil and Laterite soil.
• Layers of Soil includes Topsoil or Horizon A, Subsoil or Horizon B, Regolith or Horizon C and Bedrock or Horizon R.

Mineral Riches 

Soil is an important resource which determines the diversity of an area’s life. The outermost layer of our Planet is called the crust and a range of nutrients are given to life-forms by the minerals contained in this layer. But if the minerals are wrapped up in enormous rocks, these minerals would not be accessible to organisms. The rocks at or near the Earth’s surface are broken down over long periods of time, thousands and millions of years, by various physical, chemical and some biological processes. Factors responsible for mineral formation mentioned in natural resources class 9 notes are:

1. The Sun: Throughout the day, the sun heats up rocks so that they expand. These rocks cool down at night and contract. Since all segments of the rock do not expand and contract at the same time, cracks are produced and the large rocks eventually break up into tiny pieces.
2. Water: Water assists in the formation of soil through two ways. Due to uneven heating by the Sun, water could get into the cracks of the rocks formed. This water freezes later, causing the cracks to expand. Or else, over long periods of time, water wears away even hard rocks through quick moving water which also brings, downstream, large and small pieces of rock with it. Such rocks rub the resulting abrasion causing the rocks to wear down into smaller and smaller fragments against other rocks and transform it into soil over a period of time.
3. Wind: Strong winds often erode rocks in a manner similar to the way water rubs against rocks and wears them down. The wind also brings, as water does, sand from one location to another.
4. Living Organisms also influence soil formation as well. The lichen also grows on the rocky soil. They release some substances during their growth that cause the rock surface to crumble down and form a thin layer of soil. Other small plants, such as moss, are now able to grow on this surface and cause the stone to further break up. Often the roots of large trees go through cracks in the rocks, and as the roots get thicker, the crack becomes larger.

Pollution and its Types

Another topic in our natural resources class 9 notes is Pollution. It is the contamination of Natural Resources with unwanted substances that leads to adverse changes. Here are the different types of Pollution:

• Air Pollution: Mixture of solid particles and gases in the air leads to Air Pollution. The air around us gets contaminated by fumes, smoke, dust, etc. Some reasons for Air Pollution are car emissions, burning of fossil fuels, etc.
• Water Pollution: When contaminated water or chemicals enter water bodies affecting water organisms, then it is known as Water Pollution. Water gets contaminated by Industrial waste, chemicals, sewage etc. It can further be divided into various kinds, to know more read our blog on types of water pollution.
• Soil Pollution: Soil Pollution is caused due to the presence of chemicals and other harmful substances like garbage, fertilizers etc. that contaminate the soil. Soil Pollution is part of land degradation. 

Also Read: How to Write an Essay on Pollution?

Bio-geo-chemical Cycles

A consistent interaction between biotic and abiotic segments of the biosphere makes a framework, and this flow of segments, structures a cycle called the bio-geo-chemical cycle. Major Bio-geo-chemical Cycles of Natural Resources are:

Water Cycle

The Water Cycle is defined as the entire process in which water evaporates and falls on the land as rain and then flows back into the sea through rivers. As this statement seems to suggest, this cycle is not as straight-forward and easy. Any of the water that falls on the ground does not drain back into the sea immediately. Some of it seeps into the soil and becomes part of the fresh-water underground reservoir. Any of this underground water makes its way through springs to the surface. 

Water is capable of dissolving a great number of substances.  Some of them get dissolved in the water as water passes through or over rocks containing soluble minerals. Thus, rivers bring many nutrients from land to sea, and marine life utilizes them.

Nitrogen Cycle

Process by which nitrogen in the air changes from simpler to complex molecules and vice versa is called the Nitrogen Cycle. Nitrification is a process of fixing Nitrogen in the Atmosphere, which is done by bacteria like Rhizobium in Soil. Lightning and high temperatures convert nitrogen to oxides, which dissolves in water forming nitrous acids, etc. Another group of bacteria converts nitrates into free nitrogen, and this process is named denitrification. 

Nitrates and nitrites are usually taken up by plants and converted into amino acids that are used to produce proteins. In order to produce other complex nitrogen-containing compounds, several other biochemical pathways are used. Animals are eventually eaten by these proteins and other complex compounds.

Carbon Cycle

 When CO2 is used by plants to perform photosynthesis to produce organic compounds, then these plants are eaten by animals, and their decomposition releases CO2 back into the Atmosphere. This is known as the Carbon Cycle. When animals and plants die, bacteria present in the soil acts upon them and converts compounds of nitrogen to nitrites and notifies. Plants and animals which are buried and do not decompose during this process form coal and petroleum.

Through use of glucose to provide living organisms with energy involves the respiration process in which oxygen can or may not be used to turn glucose back into carbon dioxide. This carbon dioxide goes back into the atmosphere subsequently.

The Greenhouse Effect

The glass absorbs heat, so the temperature within a glass enclosure is much higher than the surrounding temperature. This phenomenon was used to create an enclosure where, in colder climates, tropical plants could be kept warm during the winters. They call such enclosures greenhouses. Greenhouses have given an atmospheric phenomenon their name as well. Increasing the percentage of such gases in the atmosphere will lead to a rise in global average temperatures, and this is called the Greenhouse Effect. One of the greenhouse gases is carbon dioxide. A rise in the atmospheric carbon dioxide content will allow the atmosphere to absorb more heat and contribute to global warming.

Ozone Layer

In the form of a diatomic molecule, elemental oxygen is usually found. However, a molecule that contains three oxygen atoms is contained in the upper reaches of the atmosphere. This could imply an O3 formula and this is referred to as Ozone Layer. Where it is located, it performs an important role. It absorbs the sun’s harmful radiation. This prevents such dangerous radiation from reaching the earth’s surface where several types of life can be damaged. It has recently been discovered that this layer of ozone has been depleted. In the atmosphere, numerous man-made compounds such as CFCs (carbon compounds that have both fluorine and chlorine that are very stable and not degraded by any biological process) have been found to survive. They would react with the molecules of ozone until they entered the ozone layer. This resulted in the ozone layer being diminished, and a hole in the ozone layer above Antarctica was recently discovered.

If the ozone layer declines further, it is hard to imagine the impact on life on Earth, but many people believe it would be best not to take risks. Such individuals support working to stop any further damage to the ozone layer.

This brings us to the end of Natural Resources class 9 notes! Stay tuned with Leverage Edu for more information on class 9th syllabus, scholarships, educational trends and more!