Food, Shelter & Water • Topic 3 of 3

Water: Sources, Uses & Conservation

Water is essential for all living things. Its sources are rain, rivers, ponds, lakes, wells, springs, tube-wells and the sea. Sea water is salty and cannot be drunk directly; rivers, ponds, lakes and wells give fresh water. We use water for drinking, cooking, bathing, washing, cleaning, growing crops (irrigation), and in factories. The water cycle keeps moving water around the Earth: heat from the Sun causes evaporation (water turns to vapour), the vapour rises and cools to form clouds by condensation, and falls back as rain, snow or hail (precipitation), which collects in rivers, lakes and oceans -- and the cycle repeats. Water is becoming scarce because of growing population, waste, pollution and uneven rainfall, so conservation matters: close taps while brushing, fix leaks, reuse water, water plants in the cool evening, and harvest rainwater. Rainwater harvesting means collecting and storing rainwater (in tanks or by letting it soak into the ground) to recharge groundwater and the wells. Dirty or contaminated water spreads water-borne diseases such as cholera, typhoid, diarrhoea, dysentery and jaundice, so water should be boiled, filtered or otherwise purified before drinking.

✅ Solved examples

1. In the water cycle, the process by which water from rivers and seas turns into water vapour due to the Sun heat is called:
Evaporation. The vapour later cools and condenses into clouds, which fall as rain (precipitation).
2. Collecting and storing rainwater so that it recharges the groundwater and wells is known as:
Rainwater harvesting -- an important method of water conservation, especially in areas facing water scarcity.
3. Cholera, typhoid and diarrhoea spread mainly through:
Drinking dirty or contaminated water -- they are water-borne diseases. Boiling or filtering water before drinking prevents them.
4. Why can we not drink sea water directly even though the sea holds a huge amount of water?
Sea water is salty (saline) and unfit for drinking. We need fresh water from rivers, ponds, wells and rain.

✏️ Practice — try these, take hints as needed

1. Turning off the tap while brushing teeth is an example of water:
Saving water for the future.
Opposite of wasting.
Conservation
2. In the water cycle, water vapour cools and changes into tiny water droplets forming clouds. This process is:
Comes after evaporation.
Vapour to liquid.
Condensation
3. Rain, snow and hail falling from clouds back to the ground is together called:
The third step of the water cycle.
Begins with P.
Precipitation
4. Which of these is a source of fresh (not salty) water?
Not the sea.
A dug source of underground water in a village.
Well (also river, pond, lake, rain)

📝 Topic test — 8 questions

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