1. Water and its uses :

(i) Water is a very important fluid that is essential for all living beings. Our body contains 70% of water and blood contains 98% of water.

(ii) We need water for drinking, bathing, cooking, washing, etc. It is required in very large amounts for agriculture and in industries.

2. Where do we get water from?

(i) Surface water consists of oceans and seas, rivers, lakes, streams and ponds.

(ii) Water present in rivers, lakes and streams are formed by melting of snow on mountains and from rain.

(iii) The water collected under the ground is called groundwater.

(iv) The level of water under the ground is called water table.

3. Forms of Water:

Water is available naturally in three forms:

(i) Solid form: Water is present in the form of ice.

(ii) Liquid form: Water in liquid form is present in oceans, seas, lakes, rivers, underground water, etc.

(iii) Gaseous form: When water is heated, it turns into water vapour.

3. Water cycle :

(i) The natural circulation of water in nature is called the water cycle.

(ii) There are three main processes through which water is released back into the atmosphere and vice versa. They are: evaporation, condensation and precipitation.

(iii) Evaporation is a phenomenon in which the liquid goes into the vapour state at a temperature below its boiling point.

(iv) Condensation is the process in which the water vapour cools down to form tiny water droplets. The formation of clouds and rains are the result of condensation.

(v) Sometimes, big drops of water solidify into ice and fall as pieces of ice known as hailstones.

(vi) The falling of large sized drops on the earth in the form of rain is also called precipitation.

4. Droughts - Water Scarcity

Drought can be defined as a prolonged period of unusually dry weather in an area where some rain might normally be expected.

5. Floods a natural hazard

Floods are the most frequent type of natural disaster and occur when an overflow of water submerges land that is usually dry.

6. Methods of Water Conservation :

(i) Water Management

The most important method of water conservation is to avoid wastage of water and the process starts at home.
Dams are built to store water and to prevent flooding during excessive rainfall.

(ii) Rainwater harvesting

The process of collecting rainwater and storing it for later use on rooftops of the buildings is called rainwater harvesting.
Rooftop rainwater harvesting is a traditional technique in which rainwater is collected from the roof top and allowed to go into a storage tank through pipes.
In drain water harvesting, the rainwater from the roadsides goes directly into the ground into pits, trenches, and dug wells which can be used later.

A well is circular in shape and a step well is in shape.

Important Questions on Water

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