Concept: 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.
Important sources of water:
- 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.
- Snow and glaciers:
- 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 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.
Types of water:
- Surface 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.
- Underground water:
- 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.
Uses of water:
Water is used for various purposes. Some of them are described below—
- 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.
- Domestic use:
- 4% of water available is used for domestic purposes.
- It includes washing, cleaning, drinking, cooking, flushing toilets and irrigating small plants and lawns.
- 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.
- 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.
Atmosphere: The layer of a mixture of gases surrounds the earth
Lithosphere: : The outer solid part of the earth comprising rocks and soil.
Hailstorm: A type of precipitation that is a mixture of rain and hard ice chunks.
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.