NCERT Solutions for Class 5 EVS Our Wondrous World Chapter 1 Water – The Essence of Life

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Discuss

1. Do you think we can drink the water present in the oceans?
See AnswerNo, we cannot drink ocean water because it is very salty. If we drink it, we might fall sick. It is not good for our body.

2. What can ocean water be used for?
See AnswerOcean water can be used to get salt. It is also used in big factories for cooling machines. Some people clean ocean water to use it, but it needs special machines.

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Activity 1

Where can we find freshwater? Identify the different freshwater sources from the images given below and write their names.

Answer:

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Activity 2

Take a steel glass. Put some ice cubes in it. Observe the small water droplets forming on the glass.
(a) Where do these water droplets come from?
See AnswerThe water droplets come from the air. When the cold glass touches the warm air, the water vapour turns into droplets.

(b) What happens to the ice cubes after they are left in the glass for some time?
See AnswerThe ice cubes slowly melt and turn into water.

(c) If we heat water, what will happen to it?
See AnswerIf we heat water, it starts to boil and changes into steam.

What forms of water do you see in the above activity?
See AnswerI see ice (solid), water (liquid) and steam (gas).

Answer:

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Activity 3

• Take a transparent bag.
• Use a marker to draw the sun, clouds, trees and arrows on it as shown in the picture.
• Fill one-third of it with coloured water.
  Tip: You can use blue paint or food dye for this.
• Seal the bag tightly to prevent any leaks.
• Place it in the sunlight.
• After a few hours, observe the changes inside the bag.

Answer:

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Activity 4

• Take a transparent glass.
• Fill half of it with soil.
• Slowly pour water into the soil using a spoon.
• Observe what happens.

See AnswerWhen we pour water slowly into the soil-filled glass using a spoon, we observe that the water starts disappearing from the surface. It goes down into the soil. This happens because the soil soaks the water and the water moves through the tiny spaces between the soil particles. Some of it settles at the bottom of the glass. This activity shows how rainwater seeps into the ground in real life. The water that goes deep under the soil becomes groundwater, which we later use through wells, borewells and handpumps. This experiment helps us understand the importance of having open soil and green areas for groundwater recharge. In cities with cemented roads, this soaking doesn’t happen easily, so the water gets wasted or causes waterlogging.

Let us reflect

1. Match the following:
(i) Ocean water (a) Solid form of water
(ii) Snow (b) Vapour form of water
(iii) Steam (c) Not fit for drinking
(iv) Rainwater (d) Freshwater
See Answer(i) Ocean water → (c) Not fit for drinking
(ii) Snow → (a) Solid form of water
(iii) Steam → (b) Vapour form of water
(iv) Rainwater → (d) Freshwater

2. Why do you think most of the water on Earth cannot be used for drinking or farming?
See AnswerMost of the water on Earth is salty and found in oceans, so we cannot drink it or use it for farming. Only a small amount is freshwater, which is useful for us.

3. Large number of living beings live near water bodies. Why?
See AnswerLiving beings like animals, birds, and people live near water bodies because they need water for drinking, bathing, cooking, farming and staying cool. Water also helps plants and animals to grow and survive.

4. What would happen if it did not rain in your region for two years?
See AnswerIf it did not rain for two years, rivers and ponds would dry up and we would not have enough water to drink, grow crops or support animals. There could be drought and life would become very difficult.

5. What do you think happens to rainwater in a forest compared to a city?
See AnswerIn a forest, rainwater soaks into the soil easily and recharges the groundwater. But in cities, roads and buildings are made of cement, so water cannot go into the ground and gets wasted or causes floods.

6. Can you design a house or school that conserves water wisely? What would it include?
See AnswerYes, I would design a house or school with rainwater harvesting, soak pits, open ground with grass and more trees. I would also include taps that close automatically and use stored rainwater for cleaning.

1. What is the solid form of water called?
See AnswerThe solid form of water is called ice. It forms when water freezes at very low temperatures, usually below 0°C, and is seen in glaciers, ice cubes, and snow.

2. Why can’t we drink ocean water?
See AnswerOcean water is salty and contains many dissolved salts and minerals. Drinking it can make us sick because our body cannot handle that much salt safely.

3. What is the continuous movement of water in nature called?
See AnswerThe continuous movement of water from the Earth to the sky and back is called the water cycle. It includes evaporation, condensation and precipitation, happening again and again.

4. Which river flows into the Arabian Sea?
See AnswerThe Narmada River flows westward and empties into the Arabian Sea. It is one of the few rivers in India that does not flow towards the Bay of Bengal.

5. What helps fish to swim in water?
See AnswerFish use their fins to swim in water. Fins help them move forward, turn and maintain balance in water, allowing smooth and easy movement in any direction.

6. What type of water do most living beings need to survive?
See AnswerMost living beings need freshwater to survive. It is used for drinking, farming, bathing and cooking. Freshwater is found in rivers, ponds, lakes and rainwater.

7. What is groundwater?
See AnswerGroundwater is rainwater that soaks into the soil and goes deep underground. It collects between layers of soil and rocks and is drawn using wells or handpumps.

8. What helps rainwater seep into the ground?
See AnswerOpen spaces like green lawns, soil and fields help rainwater soak into the ground. This process is important for recharging underground water, especially in forests and villages.

9. Which aquatic plant floats freely and spreads quickly?
See AnswerWater hyacinth is a free-floating plant that grows fast and spreads across ponds and lakes. It does not need soil and floats on water, covering its surface quickly.

10. Why is the waxy coating on lotus leaves useful?
See AnswerThe waxy coating on lotus leaves makes them waterproof. It prevents too much water from entering the plant, helping it stay healthy and float without getting damaged.

11. Why can’t rainwater enter the ground easily in cities?
See AnswerIn cities, most surfaces are covered with cement and concrete. These hard surfaces block water from soaking into the ground, which reduces the recharge of underground water.

12. What happens when water is heated?
See AnswerWhen water is heated, it turns into steam. This steam is a gas and rises into the air. It is part of the water cycle and helps form clouds.

13. What happens when steam cools down?
See AnswerWhen steam cools down, it turns back into water droplets. This process is called condensation and it helps in forming clouds and bringing rain back to the earth.

14. What did students observe in the mustard seed activity?
See AnswerStudents saw that mustard seeds rolled down slopes, collected in low areas and followed the land’s shape—just like water flows through rivers and gathers in lakes and ponds.

15. Why is water called a lifeline?
See AnswerWater is called a lifeline because all living things—people, animals, birds and plants—need it to live. Without water, there would be no life on Earth.

1. What are the three forms of water and how do they change from one form to another?
See AnswerWater exists in three forms:
Solid – Ice
Liquid – Water
Gas – Steam or Water Vapour
Melting: Ice changes into water when heated.
Evaporation: Water changes into steam when boiled.
Condensation: Steam cools down to form water droplets.
Freezing: Water becomes ice when cooled.

2. Why is most of Earth’s water not fit for drinking?
See AnswerAround 97% of Earth’s water is in oceans and is salty.
Salty water cannot be used for drinking or farming.
Only a small part (about 3%) is freshwater.
Out of this, most freshwater is frozen in glaciers.
Very little water is available for direct human use.

3. What is the water cycle? Explain its steps.
See AnswerThe water cycle is the continuous movement of water in nature.
Evaporation: Sun heats water in rivers, lakes, oceans.
Condensation: Water vapour rises and cools to form clouds.
Precipitation: Water falls as rain, snow or hail.
Collection: Water collects in rivers, lakes and oceans again.

4. How does a river flow and what decides its direction?
See AnswerRivers usually start from mountains or highlands.
Water flows downhill due to gravity.
The shape of the land decides the river’s path.
Rivers can curve, split or slow down depending on slopes.
Some rivers flow eastwards (e.g. Ganga), others westwards (e.g. Narmada).

5. What happens to rainwater after it falls on the ground?
See AnswerSome water flows into rivers, lakes, and ponds.
Some water is soaked by the soil.
That soaked water goes deep underground and becomes groundwater.
In cities, cemented areas stop water from soaking.
In forests and open lands, water easily recharges the soil.

6. What are the differences between animals on land and animals in water?
See AnswerAnimals on Land Animals in Water
Use lungs to breathe air Use gills to breathe underwater
Walk using legs or feet Swim using fins or body movement
Body covered with fur or skin Body often covered with scales
Live in burrows, nests, forests Live in ponds, rivers, seas.

7. What are some common aquatic plants and their features?
See AnswerLotus and Water Lily:
Roots in pond bed, flowers float on water
Waxy leaves keep them dry
Water Hyacinth:
Floats freely on water
Spreads quickly
Reeds:
Grow along pond edges
Tall and grass-like
Hydrilla:
Fully underwater
Helps oxygenate water

8. How can we help in groundwater recharge?
See AnswerAvoid cementing all open spaces.
Use soak pits in houses and schools.
Plant more trees and create green areas.
Store and reuse rainwater through rainwater harvesting.
Keep ponds, lakes and rivers clean and unclogged.

9. What is the role of the sun in the water cycle?
See AnswerHeats up water in rivers, lakes and oceans.
Causes evaporation, turning water into vapour.
Vapour rises and cools to form clouds.
Sun’s heat starts the entire cycle again.
Without the sun, the water cycle would stop.

10. How is the journey of a river important for life around it?
See AnswerProvides water for drinking, farming and bathing.
Supports many living beings—plants, animals, and humans.
Carries nutrients and minerals to fields.
Cultural and spiritual importance in India.
Helps recharge groundwater and fill lakes and ponds.