Sources and Uses of water

Water is an essential natural resource. Along with air and soil, it plays a vital role in the existence of life on earth. Water is made up of hydrogen and oxygen in a ratio of 2:1. 71% of the earth’s surface is covered with water in the form of seas and oceans.

• Oceans cover a significant portion of the earth.
• Water found in oceans contains salts and minerals.
• For this reason, ocean water is not suitable for drinking and domestic purpose.

• They comprise 2% of the total water available on earth.
• However, water from snow and glaciers is fresh and does not contain excessive salts and minerals.
• Hence, glaciers and snow fulfil 98% demand for freshwater.
• Glaciers and snow melt to form water that reaches us in the form of rivers.

Importance of Water in the Human Body:

• 70% of our body comprises water.
• Water participates in vital bodily processes like digestion, circulation and excretion.
• Water is important for the overall functioning of our bodies.
• Humans can survive without food for some days but not without water.

• The water that flows on the earth’s surface is called surface water.
• Surface water is available in the form of water in rivers, oceans, seas and lakes.

• The rainwater that gets infiltrated through the soil reaches the deeper layers of soil and accumulates to form a water reserve called an aquifer.
• It is generally found in the bedrock where the hard stones do not allow passage of water. Thus, the water gets collected in the cracks and holes.
• Underground water is pumped using tubewells and handpumps.
• In some places, the underground water is available in the form of springs.

• Out of the total freshwater available on the earth’s surface, 84% of the water is used for irrigation.
• Water for irrigation is provided through canals and tubewells.

• 12% of the freshwater available is used for industrial uses.
• Water is used for fabricating and making dyes.
• Water also plays the role of a coolant in thermal power plants.
• It is an important solvent that can dissolve most compounds in it and hence plays a vital role in the chemical industry.

Water Cycle:

• It is the cyclic process of the movement of water from the atmosphere to the lithosphere and then back to the atmosphere.
• The water cycle is a continuous process and depends on different environmental factors.
• It comprises the following steps—

• The conversion of water from liquid to gaseous form is called evaporation.
• Water from seas, oceans, lakes etc., evaporates due to the sun’s heat.
• Evaporation depends on temperature and wind.
• The evaporation rate is more on hot and windy days than on cool days or rainy days.

• The conversion of water vapour back into the liquid state is called condensation.
• As the water vapour rises upward, they start to cool due to the low temperatures in the upper layers of the atmosphere.
• It leads to the formation of water droplets which accumulate to form clouds.
• The water droplets condense to create fog and dew when the temperature becomes too low.

• The reaching of evaporated water back to the lithosphere in the form of rain, sleet, drizzle or snowfall is called precipitation.
• Drizzle, rain, sleet, and snowfall are the different forms of precipitation.

 

• When the temperature is low during winters, the water droplets get converted into ice or snow, leading to hailstorms or snowfall, respectively.
• Once the evaporated water reaches the lithosphere, the cycle repeats itself and starts with evaporation again.

• The process of seeping water into the deeper layers of soil is called infiltration.
• Infiltration replenishes the groundwater level.
• This process is affected by the building of cemented roads. As cement is not porous, it does not allow the water to percolate into the soil.
• Hence, we should always keep some parts around our houses bare or covered with grass so that water can reach the deeper layers of soil.

Did You Know?

• Fogbow is a phenomenon similar to that of a rainbow which appears when the sunlight gets refracted by the fog particles.
• Water is the best solvent on earth which can dissolve many solutes in it.
• Cucumber has 95% of water in it.
• Drinking too much water can lead to a fatal phenomenon called water intoxication.