CLASS 6 · SCIENCE · CHAPTER 8

A Journey through States of Water

Simple, student-friendly solutions to all 10 end questions and sample answers for the chapter’s main water-state, evaporation, condensation, and water-cycle activities.

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Textbook pages 161–162

Question 1

Which statement best describes condensation? (i) Water changing into vapour (ii) Liquid changing into gas (iii) Clouds forming from tiny drops (iv) Water vapour changing into liquid.

Steps only

(iv) Water vapour changes into liquid.

Answer

(iv) The conversion of water vapour into its liquid state.

Question 2

For which processes is evaporation very important? (i) Colouring with crayons, water colours, acrylic colours, or pencil colours. (ii) Writing with a pencil, ink pen, or ball-point pen.

Steps only

(i) Water colours (ii) ink pen

Answer

(i) Water colours.
(ii) Ink pen. Water evaporates from the water colours and liquid ink as they dry.

Question 3

Why can the space around natural grass feel cooler than the space around green plastic grass?

Steps only

Natural grass evaporates water and cools the air; plastic grass does not.

Answer

Natural grass releases water that evaporates and cools the surroundings. Plastic grass does not do this, so the area around it can feel warmer.

Question 4

Give examples of liquids other than water that evaporate.

Steps only

Perfume, petrol, and spirit evaporate; keep flammable liquids away from fire.

Answer

Perfume, petrol, spirit, and nail-polish remover are examples. Some are flammable, so they must be kept away from fire.

Question 5

A fan cools us, so why does it also help wet clothes dry?

Steps only

A fan moves moist air away, speeding evaporation; evaporation also causes cooling.

Answer

Moving air carries water vapour away from the clothes, so more water evaporates and the clothes dry faster. Evaporation takes heat, which is why the clothes or skin can feel cool.

Question 6

Sludge removed from drains is left in heaps for a few days before transport. How does this reduce cost and improve safety?

Steps only

Water evaporates, so the sludge is lighter and less runny to transport and handle.

Answer

Evaporation removes some water, making the sludge lighter, less liquid, and cheaper to transport. It can also reduce splashing, though workers still need protection.

Question 7

Name household activities that involve evaporation. How does knowing about evaporation help us?

Steps only

Clothes, floors, sweat, and utensils dry by evaporation; spread items to dry faster or cover liquids to slow it.

Answer

Examples: drying clothes, a mopped floor drying, sweat drying, and utensils drying. We can speed drying by spreading items in warm, moving air, or slow evaporation by covering liquids.

Question 8

How is water present in the solid state in nature?

Steps only

As glaciers, ice caps, snow, and hail.

Answer

Water occurs as ice in glaciers and ice caps, as snow on mountains, and as hail.

Question 9

Reflect on: “Water is our responsibility before it is our right.”

Steps only

Use water carefully and keep it clean so it remains available to everyone.

Answer

The statement means we should protect and use water carefully, not waste or pollute it. This helps ensure clean water is available to everyone, now and in the future.

Question 10

A two-wheeler seat becomes very hot in the Sun. How can you cool it?

Steps only

Move it to shade or wipe with a damp cloth; evaporation cools the seat.

Answer

Park in shade. A damp cloth can also cool the seat as its water evaporates; wipe it dry before sitting.

Chapter Questions and Activities

Textbook pages 143–160

Question Opening prompt

Are ice and water the same substance? How can you check?

Steps only

Yes; they are the same substance in different states. Ice melts into water.

Answer

Yes. Ice and liquid water are the same substance in different states. Let an ice cube melt and observe that it becomes water.

Question Prompt 1

Where does water from a puddle go when it disappears?

Steps only

It may seep into the ground and evaporate into the air.

Answer

Water can seep into the ground and evaporate into the air. Both processes may happen.

Question Activity 8.2

How can you test whether water disappears by seeping through a steel plate?

Steps only

Water disappears from the top while the underside stays dry: it evaporates.

Answer

Put water on a dry steel plate and check underneath: it remains dry while the top water gradually evaporates. This supports that it did not seep through the plate.

Question Prompt 2

Where does water sprinkled on a hot pan go?

Steps only

It evaporates; visible steam is tiny water droplets.

Answer

It evaporates into water vapour. The visible “steam” nearby is tiny droplets formed when vapour cools.

Question Prompt 3

What should a labelled drawing of water disappearing show?

Steps only

Liquid water → evaporation → water vapour in air.

Answer

Show liquid water changing to invisible water vapour and spreading into the air. Label it evaporation.

Question Prompt 4

Where do droplets on the outside of a cold glass come from?

Steps only

Water vapour in air condenses on the cold glass.

Answer

They come from water vapour in the air. It cools on the cold glass and condenses into liquid drops.

Question Activity 8.4

How can you test whether water outside a cold tumbler came from inside or from air?

Steps only

Mark the level and weigh it; unchanged inside level with outside drops supports condensation.

Answer

Mark the inside water level and weigh the covered cold tumbler. If the level stays the same while outside droplets form and the measured mass increases, the droplets came from air by condensation.

Question Prompt 5

Where do morning dew drops and drops under a lid above boiling water come from?

Steps only

They form by condensation of water vapour on a cool surface.

Answer

Both form when water vapour cools on a surface and condenses into liquid drops.

Question Activity 8.5

Compare ice, liquid water, and water vapour by shape, flow, and spreading.

Steps only

Ice holds shape; liquid flows and takes container shape; vapour spreads through available space.

Answer

Ice: fixed shape; does not flow/spread. Water: takes container shape; flows and spreads. Water vapour: no fixed shape; spreads to fill available space.

Question Prompt 6

Give examples of solids, liquids, and gases.

Steps only

Solids: stone/wood. Liquids: milk/oil. Gases: oxygen/carbon dioxide.

Answer

Solids: stone, wood, glass. Liquids: milk, oil, juice. Gases: oxygen, carbon dioxide, water vapour.

Question Prompt 7

How can we smell food cooking from outside the kitchen?

Steps only

Smell particles spread through air to our nose.

Answer

Smell particles spread through the air and reach our nose.

Question Activity 8.6

Complete the state-change diagram between solid, liquid, and gas.

Steps only

Solid melts to liquid; liquid freezes to solid; liquid evaporates to gas; gas condenses to liquid.

Answer

Solid —melts→ liquid; liquid —freezes→ solid; liquid —evaporates→ gas; gas —condenses→ liquid.

Question Prompt 8

How can we change ice to water, water to vapour, and water back to ice?

Steps only

Heat: ice→water→vapour. Cooling: water→ice.

Answer

Heat melts ice and can turn liquid water into vapour. Cooling water makes it freeze into ice.

Question Prompt 9

Which factors can make water evaporate faster or slower?

Steps only

More area, heat, and wind speed it up; humidity slows it.

Answer

Evaporation is faster with larger exposed area, warmer conditions, and moving air. High humidity slows it.

Question Activity 8.7

In the cap-and-plate investigation, what should stay the same, what changes, and what is measured?

Steps only

Same water and conditions; change surface area; measure drying time.

Answer

Keep water amount and surroundings the same; change exposed area; measure evaporation time. The plate should dry first.

Question Activity 8.8

What do you expect when equal water amounts are left in sunlight and shade?

Steps only

Sunlit water usually evaporates faster.

Answer

Water in sunlight usually evaporates faster and dries sooner than water in shade.

Question Prompt 10

Why is water in an earthen pot cool? Why does a fan cool us?

Steps only

Evaporation from the pot and from our skin removes heat and cools.

Answer

Water that seeps through the porous earthen pot evaporates and cools the remaining water. A fan helps sweat evaporate, cooling our skin.

Question Prompt 11

How can you help clothes dry on a rainy day?

Steps only

Spread them out in moving air in a sheltered place.

Answer

Spread clothes in a ventilated sheltered place and use moving air if possible. High humidity slows drying, so avoid crowding or covering the clothes.

Question Activity 8.9

How does a pot-in-pot cooler work?

Steps only

Evaporation from damp sand and the outer pot cools the inner pot.

Answer

Water evaporates through the outer pot and damp sand, removing heat and cooling the inner pot. Keep the sand moist and allow airflow.

Question Prompt 12

How does water vapour form clouds and rain?

Steps only

Rising air cools; vapour condenses into clouds; larger drops fall as rain.

Answer

Rising moist air cools; vapour condenses into cloud droplets. The droplets join, grow heavy, and fall as rain (or snow/hail in cold conditions).

Question Activity 8.10

What does adding a tiny piece of burnt paper to the squeezed-bottle cloud activity show?

Steps only

Dust-like particles help vapour condense into cloud droplets.

Answer

Tiny particles help water vapour condense into visible droplets. The burnt paper provides particles, making a hazy cloud easier to see. Perform only with teacher supervision.

Question Activity 8.11

Describe how to label a water-cycle diagram with ocean, lake, river, groundwater, cloud, evaporation, condensation, rain, and snow.

Steps only

Evaporation → clouds by condensation → rain/snow → rivers and groundwater → ocean.

Answer

Water evaporates from oceans, lakes, rivers, and wet land; vapour condenses into clouds; rain or snow falls; surface water and groundwater return toward rivers and oceans.

Question Activity 8.1

What do you observe when an ice cube is left on a table?

Steps only

Ice melts into liquid water.

Answer

The ice melts into water. Ice and water are the same substance in different states.

Question Prompt 13

Why should we use water wisely and avoid pollution?

Steps only

Clean usable water is limited; conserve it and prevent pollution.

Answer

Usable freshwater is limited and all living things need it. Saving water and preventing pollution protect it for everyone.

Question Prompt 14

Can water vapour be present even when we cannot see it?

Steps only

Yes. Vapour is invisible; visible steam is tiny droplets.

Answer

Yes. Invisible water vapour is present in air. White “steam” is tiny liquid-water droplets, not the vapour itself.