Chapter 8. A Journey through States of Water Science Curiosity class 6 in English Medium ncert book solutions NCERT TextBook Questions With Answers

Chapter 8. A Journey through States of Water

The following NCERT textbook exercise is prepared according to the latest NCERT Curiosity textbook and CBSE pattern. Each answer is written in simple, original, and student-friendly language to help learners understand the concepts clearly while preparing for school examinations.

NCERT Textbook Exercise

Read each question carefully before answering. Wherever required, suitable explanations have been provided to improve conceptual understanding.

Question 1. Which of the following best describes condensation?

(A) The conversion of water into its vapour state.
(B) The process of water changing from a liquid into gaseous state.
(C) The formation of clouds from tiny water droplets.
(D) The conversion of water vapour into its liquid state.

Answer: (D) The conversion of water vapour into its liquid state.

Explanation: Condensation is the process in which water vapour loses heat and changes back into liquid water. This process is responsible for the formation of dew, water droplets on a cold glass, and clouds. :contentReference[oaicite:0]{index=0}

Question 2. Identify in which of the following processes evaporation is very important.

(i) Colouring with

(A) Crayons
(B) Water colours
(C) Acrylic colours
(D) Pencil colours

Answer: (B) Water colours

Explanation: Water colours dry because the water present in them evaporates, leaving the coloured pigment on the paper.

(ii) Writing on paper with

(A) Pencil
(B) Ink pen
(C) Ball point pen

Answer: (B) Ink pen

Explanation: The liquid ink dries after the solvent evaporates, making evaporation an important part of writing with an ink pen. :contentReference[oaicite:1]{index=1}

Question 3. We see green coloured plastic grass at many places these days. Space around natural grass feels cooler than the space around plastic grass. Can you find out why?

Answer:

Natural grass contains water. Water continuously evaporates from the leaves through transpiration and evaporation. During evaporation, heat is absorbed from the surroundings, producing a cooling effect. Plastic grass does not contain water and therefore cannot produce this cooling effect. As a result, the area around natural grass feels cooler than the area around artificial grass.

Question 4. Give examples of liquids other than water that evaporate.

Answer:

Some common liquids that evaporate are:

• Hand sanitiser
• Perfume
• Petrol
• Alcohol
• Nail polish remover (acetone)

Explanation: These liquids change into vapour when exposed to air. Some of them evaporate much faster than water.

Question 5. Fans move air around, creating a cooling sensation. It might seem strange to use a fan to dry wet clothes since fans usually make things cooler, not warmer. Normally, when water evaporates, it requires heat, not cold air. What do you think about this?

Answer:

A fan increases the movement of air around wet clothes. Moving air removes the water vapour formed during evaporation, allowing more water to evaporate quickly. Although the air from the fan is not hot, it increases the rate of evaporation. Therefore, clothes dry faster under a fan.

Explanation:

• Moving air increases evaporation.
• Faster evaporation removes moisture quickly.
• Hence, wet clothes dry faster even without heating.

Question 6. Usually, when sludge is removed from drains, it is left in heaps next to the drain for 3–4 days. Afterward, it is transported to a garden or a field where it can be used as manure. This approach reduces transportation cost of the sludge and enhances the safety of individuals handling it. Reflect upon it and explain how.

Answer:

Fresh sludge contains a large amount of water, making it heavy and difficult to transport. When it is left in heaps for a few days, much of the water evaporates naturally. As the moisture content decreases, the sludge becomes lighter, easier to handle, and less likely to spread dirty water. This reduces transportation costs and improves the safety and convenience of workers handling the sludge.

Question 7. Observe the activities in your house for a day. Identify the activities that involve evaporation. How does understanding the process of evaporation help us in our daily activities?

Answer:

Activities involving evaporation:

• Drying washed clothes.
• Drying of mopped floors.
• Cooling of the body through sweating.
• Drying utensils after washing.
• Drying of wet bathrooms.

Importance of evaporation:

• Helps in drying clothes quickly.
• Keeps our body cool through sweating.
• Helps preserve food in earthen pot coolers.
• Explains why fans help dry wet surfaces faster.

Question 8. How is water present in the solid state in nature?

Answer:

In nature, water is present in the solid state as:

• Snow
• Ice
• Glaciers
• Icebergs
• Frozen lakes and rivers in very cold regions

Question 9. Reflect on the statement, "Water is our responsibility before it is our right." Share your thoughts.

Answer:

Water is one of the most valuable natural resources. Every person has the responsibility to use water wisely, prevent wastage, and keep rivers, lakes, and ponds free from pollution. Conserving water today will ensure that future generations also have access to clean and sufficient water. Responsible use of water is therefore more important than simply considering it our right.

Question 10. The seat of a two-wheeler parked on a sunny day has become very hot. How can you cool it down?

Answer:

The hot seat can be cooled by sprinkling a small amount of water on it. As the water evaporates, it absorbs heat from the seat, producing a cooling effect. Keeping the vehicle in the shade or covering the seat also helps reduce its temperature.

Explanation: This cooling takes place because evaporation absorbs heat from the surroundings before water changes into water vapour.

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