Category :
7th Class
Water : A precious Resource
Synopsis
- Water is the most essential thing for the existence of life. Water is an extremely stable compound. It does not decompose into its constituents, hydrogen and oxygen, easily.
- Water exists in three states - solid, liquid and gas.
- About \[71%\]of the earth's surface is covered with water but only \[0.006%\] of the water found on the earth is available for our use.
- The continuous cycling of water among its three forms keeps the total amount of water constant. This is known as water cycle.
- Though water is maintained by the water cycle, yet there is an acute scarcity of water in many parts of the globe.
- There is an uneven distribution of water. Much of it has resulted from human activities.
- Water in our body helps in the movement and absorption of nutrients. It also helps to control the body temperature.
- Ground water is an important source of fresh water. The availability of ground water depends on the water table of a place.
- The water table goes down if the usage is more than the replenished water through rains and seepage.
- Rapid growth of industries, increasing population, growing irrigation requirements and mismanage-ment are some of the causes for water shortage.
- Water harvesting is one of the methods of recharging ground water.
- The seeping of water into the ground is called infiltration.
- Ground water at some places is stored between the layers of hard rock below the water table is known as aquifer.
- Sewage is liquid waste. The impurities in water are called contaminants.
- Chemicals used in agriculture, factories and human waste contaminate water.
- Plants wilt and ultimately dry-up if they are not watered for a few days.
- Waste Water Treatment Plants (WWTP) clean water before its disposal by using a series of processes like filtration, sedimentation, skimming, treatment with anaerobic and aerobic bacteria, chlorination, etc.