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Lessons
- Chapter 1 – Nutrients in plants
- Chapter 2 – Nutrition in Animals
- Chapter 3 – Fibre to Fabric
- Chapter 4 – Heat
- Chapter 5 – Acids bases and salts
- Chapter 6 – Physical and Chemical Changes
- Chapter 7 – Weather, Climate and Adaptations of Animals to Climate
- Chapter 8 – Winds, Storms and Cyclone
- Chapter 9 – Soil
- Chapter 10 – Respiration in Organisms
- Chapter 11 – Transportation in Animals and Plants
- Chapter 12 – Reproduction in Plants
- Chapter 13 – Motion and Time
- Chapter 14 – Electric Current and its Effects
- Chapter 15 – Light
- Chapter 16 – Water: A Precious Resource
- Chapter 17 – Forests: Our Lifeline
- Chapter 18 – Waste water Story
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Question Bank
- Question Bank – Chapter 1 – Nutrients in Plants
- Question Bank – Chapter 2 – Nutrition in Animals
- Question Bank – Chapter 3 – Fibre to Fabric
- Question Bank – Chapter 4 – Heat
- Question Bank – Chapter 5 – Acids, Bases and Salts
- Question Bank – Chapter 6 – Physical & Chemical Changes
- Question Bank – Chapter 7 – Weather, Climate & Adaptations of Animals to Climate
- Question Bank – Chapter 8 – Winds, Storms and Cyclones
- Question Bank – Chapter 9 – Soil
- Question Bank – Chapter 10 – Respiration in Organisms
- Question Bank – Chapter 11 – Transportation in Animals and Plants
- Question Bank – Chapter 12 – Reproduction in Plants
- Question Bank – Chapter 13 – Motion and Time
- Question Bank – Chapter 14 – Electric Current & Its Effects
- Question Bank – Chapter 15 – Light
- Question Bank – Chapter 16 – Water: A Precious Resoure
- Question Bank – Chatper 17 – Forest: Our Life Line
- Question Bank – Chapter 18 – Waste Water Story
Chapter 16 – Water: A Precious Resource
Chapter 16
Water: A Precious Resource
- Water on the earth has been maintained for millions of years by various processes which make the water cycle.
- The solid form, snow and ice, is present as ice caps at the poles of the earth, snow-covered mountains and glaciers.
- Liquid water is present in oceans, lakes, rivers, and even underground. The gaseous form is the water vapour present in the air around us.
- The rainwater and water from other sources such as rivers and ponds seeps through the soil and fills the empty spaces and cracks deep below the ground.
- The process of seeping of water into the ground is called infiltration groundwater thus gets recharged by this process.
- At places the groundwater is stored between layers of hard rock below the water table. This is known as an aquifer.
- Groundwater is an important source of water.
- A level where all the space between particles of soil and gaps between rocks are filled with water is called the water table.
- This may happen due to many reasons.
- Increase in population, industrial and agricultural activities are some common factors affecting water table.
- Scanty rainfall is another factor that may deplete the water table.
- Yet another factor affecting water table could be deforestation and decrease in the effective area for seepage of water.
- Increasing population creates demand for construction of houses etc.
- This decreases the open areas like parks, and playgrounds. This, in turn, decreases the seepage of rainwater into the ground.
- Moreover a huge amount of water is required for construction work.
- Often groundwater is used for this purpose, on one hand we are consuming more groundwater, and on the other we are allowing lesser water to seep into the ground.
- This results in depletion of water table.
- Water is used by all the industries.
- Almost everything that we use needs water somewhere in its production process.
- The number of industries is increasing continuously.
- Water used by most of the industries is drawn from the ground.
- A majority of farmers in India depend upon rains for irrigating their crops. Irrigation systems such as canals are there only in a few places.
- Even these systems may suffer from lack of water due to erratic rainfall.
- Farmers have to use groundwater for irrigation.
- Population pressure on agriculture forces increasing use of groundwater day by day.
- This results in depletion of water table.
- Some places have good amount of rain and are water-rich. On the other hand, there are deserts which have scanty rainfall.
- Excessive rains cause floods, whereas the absence of rains results in droughts.
- Therefore, some regions in our country may have floods while others may suffer from droughts at the same time.
- Supply of water is provided by a well-planned pipe system.
- When the civic authorities supply water supply pipes leaking and a lot of water gushing out of the pipes.
- It is the responsibility of the civic authorities to prevent such wastage of precious water.
- Wastage may take place at the level of individuals also.
- We waste water while brushing teeth, shaving, bathing, washing and during many other activities.
- Leaking taps is another source of huge water wastage.
- The rainwater can be used to recharge the groundwater.
- This is referred to as water harvesting or rainwater harvesting.
- Drip irrigation is a technique of watering plants by making use of narrow tubings which deliver water directly at the base of the plant.
- If water is not available to plants,
- The green character of the planet shall be lost.
- This may mean the end of all life, for a world without plants shall mean no food, no oxygen, not enough rain, and innumerable other problems.
- Water is essential for all living beings. There can be no life without it.
- Water exists in three forms: solid, liquid and vapour.
- 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.
- Rapid growth of industries, increasing population, growing irrigation requirements and mismanagement are some of the causes for water shortage.
- We need to be worried about the wastage during the supply of water through pipes, the leaking taps in buildings and other places.
- Unnecessary use of water and overdrawing from groundwater should be avoided. Recharge of water to the ground should be increased.
- The need of the hour is that every individual uses water economically.