Study notes on Water for CTET & TET Exam

Updated : Jul 17, 2018, 17:00
By : Ashish

Meaning of Water:

After air, the substance which is of utmost importance for all organisms including humans is water. Without water, we cannot imagine life. We use water daily for bathing, washing, drinking and for many other purposes. 

Sources of water:

The largest source of water on Earth is sea which covers over two-thirds of the Earth's surface. Sea water is salty and cannot be used in agriculture and homes. River, lake, pond, well, rain and snow are other sources of water. In addition to this, underground water is also a source of water, underground water is not suitable for drinking and cooking. There are many germs and impurities in this water, so to make this water potable and useful several methods are applied.

People in cities get water from taps, water has to travel long distances to reach the tap, in cities mostly the water is stored in the reservoir by the pump. This water is transported to the institute where it is cleaned. Here the water is filtered through layers to remove sand and dirt. Some chemicals such as chlorine are used in the water to kill microbes. This cleaned water through main pipes is sent to different parts of the city. Trough small pipes water are transported to each household. Places where tap water is not available, people receive water from rivers, lakes, springs, and wells. By boiling, filtering and using chemicals such as potassium permanganate they make the water potable.

Pure water is not derived from natural sources. Salts and gas are dissolved in the water which adds flavors to water. The diluted substance is present in Wells, tube wells, and rainwater. When harmful substances are present in the water we could not drink the water. Sometimes the water-insoluble substance is present in the water which is removed by the filter.

There is a lot of salts dissolved in the water is called brackish water, sea water is salty but the rainwater is not saline, water from other sources with certain circumstances may be saline.  

General properties of water:

  • Pure water is colorless, odorless, independent and transparent.
  • Water is a good solvent, i.e., it is capable of many fluids themselves resolutive.
  • Water from rivers, lakes, and wells contain salts dissolved in different amounts, due to this dissolved salts in the water it is saline.
  • Water-solid (ice), liquid (water) and gas (vapor) can live in three states.
  • Pure water freezes at 0 °C and at 100 °C  it boils.
  • Water on heating at 0-4 °C it shrinks due to this density is maximum at 4 °C happens. This is why in cold regions snow forms on the surface of the lake but below the surface water are still in liquid form and thus aquatic creatures can live in those regions.
  • The vaporization temperature of the water is high.
  • Water's heat capacity is more and heat conductivity is less.
  • Water is an essential component for all organisms.

  Key Facts:

  • The human body contains about 70 percent water. Some fruits and vegetables contain 90 to 95 percent of water.
  • All animals and plants require water. Humans cannot survive without water.
  • A person drinks on an average of 2 liters of water per day. It is helpful in maintaining the temperature of the human body.
  • Water is essential for many reactions occurring in the human body.
  • Animal gets water from pond, springs, and rivers. Plant from its roots takes water from the soil.
  • Plants use this water for their life process. Most life processes of plants and animals occur through the water.
  • In addition, humans require water in various functions. The plants require too much water.
  • For the irrigation of fields, water is required. The use of water in agriculture is more.

  Hardness and softness of water:

  • Many substances dissolve in water, that is water is a good solvent, the dissolved salts can change the properties of water.
  • The presence of calcium and magnesium salts in water are responsible for the hardness of water. The higher the concentration of minerals, which include magnesium and calcium, the harder the water is. Sodium carbonate is soluble but calcium carbonate and magnesium carbonate are insoluble. The water is softened because it no longer contains dissolved calcium ions and magnesium ions. 
  • Hard water can be suitable for drinking but unsuitable for certain tasks.
  • Due to bicarbonate compounds in the water, there is temporary hardness and if chloride and sulfate dissolve in water the stiffness will be permanent.

  Characteristics of Drinking Water:

  • Water is colorless, unattached, clean and transparent.
  • It should be free from suspended impurities and different bacteria.
  • Some dissolved minerals are beneficial to our health, and to make water delicious.
  • Generally wells and potable water wells.
  • By using contaminated water, Typhoid, Cholera, dysentery etc. as terrible diseases spread.
  • Bacteria present in the Contaminated water can be destroyed by boiling or by using bleaching powder or potassium permanganate.

  Water Pollution and Water Conservation:

At home, in agriculture or in the industry the used water is contaminated after use, harmful substances and several types of residues are found in used water that is known as pollutants. Sewage and waste also pollute water. Water pollution is due to the following reasons:

  • Sewage
  • human
  • Animal
  • Industrial waste discharge
  • Rotting trees and vegetation
  • Dead cattle
  • Diseases are caused by consumption of contaminated water, most rivers and lakes in our country are polluted. So every effort to control their pollution being.

  Water conservation:

Water pollution can be restricted to some extent in several ways, such as:

  • Preventing domestic, industrial and other residues falling directly in the water sources such as rivers and lakes can reduce water pollution.
  • To prevent pollution of Rivers by plants located along the rivers is strictly needed to be checked to stop these industrial wastes going into rivers.
  • Treatment of industrial wastewater must be monitored.
  • Near the laundry and clean water sources should conduct them will help keep them clean.
  • Washing clothes and cleaning kitchen utensils should not be conducted near the sources of water, this will help to keep the water clean.


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AshishJul 17CTET & Teaching Exams