Drop By Drop – Class 3 EVS Chapter 20 (CBSE NCERT)

Why Is Water Called 'Precious'?

Water covers most of our Earth, but only a very small part of it is fresh water that we can drink or use at home — the rest is salty sea water or locked up as ice. That is why every drop matters! In cities, water usually comes to our homes through pipes connected to big tanks or rivers. But in many villages, there are no taps in every house. People fetch water from a well, hand pump, pond, or a faraway river, often carrying heavy pots (called 'ghadas' or matkas) on their heads or on carts. Children sometimes even skip school to help fetch water for their family. This is why we say water should never be wasted — because someone, somewhere, is struggling hard just to get a little of it. Saving water at home means we are also helping people in places where water is scarce (very little in amount).

Sources and Words to Remember

Source of water

A place from where we get water, such as rain, rivers, lakes, ponds, wells, and hand pumps.

Well

A deep hole dug into the ground from which water is pulled up using a rope and bucket or a pulley.

Hand pump

A machine fixed over a underground water source; you push its handle up and down to bring water out.

Water scarcity

A situation where there is not enough water available for people to use easily.

Rainwater harvesting

Collecting and storing rainwater so it can be used later instead of letting it flow away and get wasted.

Reservoir

A large natural or man-made lake used to store water, often behind a dam, to supply cities and villages.

How Water Reaches Our Homes (Step by Step)

1. Step 1: Water is collected at the source — Rain fills rivers, lakes and reservoirs. This is the biggest natural source of fresh water for a whole city or village.
2. Step 2: Water is stored in a big tank or dam — Municipal corporations store river or rain water in large tanks or dams so it can be supplied slowly through the year, even in dry months.
3. Step 3: Water is cleaned (purified) — Before it reaches homes, water is filtered and treated to remove mud, germs and dirt so that it is safe to drink.
4. Step 4: Water travels through pipes — Clean water flows through a large network of underground pipes that connect to every street and building in a city.
5. Step 5: Water reaches our taps — Finally, the water comes out of the tap in our kitchen or bathroom, ready for us to use — this whole journey happens every single day without us noticing!

Worked Example: Ways to Save Water at Home

• Example 1 – Brushing teeth: If you leave the tap running while brushing for 2 minutes, about 12 litres of water can go waste. Instead, wet your brush, turn the tap OFF, brush, then turn it ON only to rinse. Saving: almost 10 litres per person per day.
• Example 2 – Washing hands: Many children keep the tap fully open while soaping their hands. Correct way: turn the tap on to wet hands, turn it OFF while applying soap, then turn it ON again only to rinse. This can save several litres every time.
• Example 3 – Leaking tap: A tap that drips even slowly can waste more than 15 litres of water in a single day (that's like wasting a full bucket!). The fix: tell an adult immediately so the leaking tap or washer can be repaired.
• Example 4 – Watering plants: Instead of using a hose (which uses a lot of water fast), use a mug or a watering can, and water plants early morning or evening so water does not evaporate quickly in the sun.

Common Mistakes Students Make

• Confusing 'source of water' with 'use of water' — river is a source, but drinking/washing are uses, not sources.
• Writing 'sea water' as a source we can directly drink — remember sea water is salty and not fit for drinking without special treatment.
• Forgetting to mention BOTH natural sources (rain, river, pond) and man-made sources (well, hand pump, tank) in answers.
• Giving only one way to save water when the question asks to 'list' — always try to give at least 3-4 points for full marks.
• Mixing up 'water scarcity' (shortage of water) with 'water pollution' (dirty/contaminated water) — these are different ideas.

Exam Tip for Full Marks

When you get a question like 'How can we save water?' or 'What are the sources of water?', always answer in clear points, not one long sentence — teachers give marks for each correct point. Use real examples from your own life, like turning off the tap while brushing, because CBSE Class 3 evaluators like relatable answers. Also remember simple key words: source, scarcity, harvesting, precious — using these words correctly in your answers shows the examiner that you understood the chapter well.

Practice Questions with Solutions

• Q: Name any four sources of water.
  A: Step 1: Think of natural sources first – rain, rivers, and ponds are natural.
  Step 2: Now think of man-made sources – wells and hand pumps are made by people.
  Final answer: Four sources of water are rain, river, well, and hand pump.

• Q: Why should we not waste water?
  A: Step 1: Remember that fresh, usable water is a very small part of all the water on Earth.
  Step 2: Recall that in many villages, people walk long distances to fetch water, so it is hard to get.
  Final answer: We should not waste water because it is limited and many people have to work very hard to get even a little of it, so every drop is precious.

• Q: What is a hand pump and how is it used?
  A: Step 1: A hand pump is a device fitted over an underground water source.
  Step 2: To use it, you push the handle up and down repeatedly.
  Step 3: This pumping action pulls water up from underground and it flows out of the spout.
  Final answer: A hand pump is a manual device used to bring underground water to the surface by pushing its handle up and down.

• Q: Give three ways in which you can save water at home.
  A: Step 1: Think about your daily activities like brushing, bathing, and washing hands.
  Step 2: Turn off the tap while brushing teeth or soaping hands.
  Step 3: Use a mug for bathing instead of a shower, and fix any leaking taps quickly.
  Final answer: Three ways to save water are: turning off the tap while brushing, using a mug instead of a shower while bathing, and getting leaking taps repaired immediately.

• Q: What happens if a tap keeps leaking for many days without repair?
  A: Step 1: A leaking tap loses water drop by drop, even when not in use.
  Step 2: Over a single day, this can add up to more than a bucket of water (around 15 litres or more).
  Step 3: Over many days, this becomes a huge amount of wasted water.
  Final answer: If a tap keeps leaking for many days, it wastes a very large amount of water uselessly, so it must be repaired as soon as it is noticed.

Frequently Asked Questions