6th Class Science Water

Water

Synopsis

• Water is one of the vital components required for life and is called the compound of life.

•  Water has many properties that makes it unique and vital.

• The primary source of water on land is rain water.

• Water in its various forms is very abundant. About two-thirds of the earth is covered with water but most of it is not fit for drinking.

• Rain, hail and snow replenish water in rivers, lakes, ponds, wells and soil.

• Clouds are formed by floating droplets of water condensed in the higher layers of the air.

•  The exchange of water between land, atmosphere and water bodies is called water cycle.

•  In the water cycle, water gets purified by the processes of evaporation and condensation.

•  All the forms of water undergo changes continuously owing to water cycle and become potable (water suitable for drinking).

• Water (from rain and snow) gets collected in the rivers, and ground water is the main source of potable water.

•  Ordinary water contains many other substances (minerals and salts) in addition to the various inpurities that are essential for life. This is because a wide variety of substances have affinity for water. Rarely do we find or use pure water.

• Water is not only used for drinking but also for various other purposes like in the cleaning, in the preparation of food by plants, separation or recovery of pure substances, sustaining aquatic life etc.

• Salinity, pollutants, bacteria, etc. make most of the water found in nature unfit for drinking.

• Plants also lose water into the air through a process called transpiration.

• Excessive rains may cause floods while lack of it for long periods may cause droughts.

• The process of collecting rain water and storing it for later use is called rain water harvesting.

• Conservation by recycling storage water, rain water harvesting, afforestation and other methods restore the balance of water on the earth.

• Deforestation, excessive use of ground water, reduction in the absorption of water by the soil and other factors cause an imbalance in rainfall and the availability of water, leading to many natural disasters.