The chapter, A Journey through States of Water, begins on a rainy morning when two students, Aavi and Thirav, notice water puddles on their school playground. By evening, some of those puddles have disappeared and the two friends begin to wonder where the water went. Aavi believes the water seeped into the ground, while Thirav believes it disappeared into the air. Both turn out to be partially right and in figuring out who is correct and why, students learn about one of the most important processes in all of science, called evaporation.
The chapter covers the three states of water, the processes that convert water from one state to another, the factors that speed up or slow down evaporation, the cooling effect of evaporation, how clouds form and the complete water cycle. Aavi and Thirav later notice water droplets forming on the outside of a cold glass of lemonade. The water droplets did not leak through the glass. They came from the air around it. This introduces condensation and from there, the chapter shows how water moves through the environment in a continuous, self-sustaining cycle. NCERT Solutions for Class 6 Science for this chapter cover all in-text, activity-based and back exercise questions, helping CBSE Board Class 6 students write accurate and well-structured answers to every type of question asked in school exams.
Download NCERT Solutions for Class 6 Science Chapter 8 PDF
Download the NCERT Solutions for Class 6 Science Chapter 8 A Journey through States of Water PDF for free and study anytime, anywhere. These solutions provide accurate, step-by-step answers to all NCERT exercise questions in simple language. Use this PDF to revise important concepts such as evaporation, condensation, the water cycle, changes in the states of water and water conservation while preparing confidently for your school exams.
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NCERT Exercise Solutions for Class 6 Science Chapter 8 A Journey through States of Water
NCERT Solutions for Class 6 Science Chapter 8 given below cover all the questions in this chapter. These solutions are prepared according to the latest CBSE Board Class 6 syllabus and are designed to help students understand the concepts clearly and write accurate and well-structured answers. By practicing these solutions regularly, students can improve their understanding of the chapter and prepare confidently for school tests and exams.
Q1. Which of the following best describes condensation?
(i) The conversion of water into its vapour state.
(ii) The process of water changing from a liquid into gaseous state.
(iii) The formation of clouds from tiny water droplets.
(iv) The conversion of water vapour into its liquid state.
Answer: (iv) The conversion of water vapour into its liquid state.
Explanation: Condensation is the process in which water vapour cools down and changes into liquid water. Water droplets that form on the outside of a cold glass are an example of condensation.
Q2. Identify in which of the given 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 in them evaporates after painting.
(ii) Writing on paper with
(a) pencil
(b) ink pen
(c) ball point pen
Answer: (b) Ink pen
Explanation: The ink dries on the paper due to evaporation of the liquid present in the ink.
Q3. We see green coloured plastic grass at many places these days. Space around natural grass feels cooler than space around the plastic grass. Can you find out why?
Answer: Natural grass releases water vapour into the air through a process called transpiration. The evaporation of this water absorbs heat from the surroundings and creates a cooling effect.
Plastic grass does not release water or undergo transpiration. Therefore, it becomes hotter and does not cool the surrounding air.
Q4. Give examples of liquids other than water that evaporate.
Answer: Some liquids other than water that evaporate are:
- Alcohol
- Perfume
- Petrol
- Nail polish remover (acetone)
These liquids change into vapour when left exposed to air.
Q5. 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 does not heat the clothes. Instead, it increases the movement of air around them.
Moving air carries away the water vapour formed during evaporation. This allows more water to evaporate quickly, so the clothes dry faster.
Although the air feels cool, it helps increase the rate of evaporation, which speeds up the drying process.
Q6. 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: When sludge is left in heaps for a few days, much of the water present in it evaporates. As a result, the sludge becomes lighter, drier and easier to handle.
This helps in two ways:
- It reduces transportation cost because the weight of the sludge decreases.
- It becomes safer and easier for workers to handle, as it is less wet and messy.
Q7. 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: Some daily activities that involve evaporation are:
- Drying washed clothes.
- Sweating during exercise.
- Drying of a wet floor after cleaning.
- Drying of washed utensils.
- Cooling of water stored in an earthen pot.
- Understanding evaporation helps us:
- Dry clothes faster by keeping them in sunlight or under a fan.
- Stay cool because sweat evaporates from our skin.
- Store drinking water in earthen pots to keep it cool naturally.
- Understand why wet surfaces become dry after some time.
Q8. How is water present in the solid state in nature?
Answer: Water is present in the solid state as:
- Ice
- Snow
- Glaciers
- Icebergs
- Hailstones
These forms are commonly found in cold regions and high mountains where the temperature is very low.
Q9. Reflect on the statement "Water is our responsibility before it is our right." Share your thoughts.
Answer: Water is essential for all living beings. We should use it carefully and avoid wasting it.
Saving water today helps ensure that there is enough clean water for future generations. Simple habits such as closing taps properly, repairing leaking pipes and collecting rainwater can help conserve water.
Therefore, it is our responsibility to protect and save water before expecting it to be available for our use.
Q10. The seat of a two-wheeler parked on a sunny day has become very hot. How can you cool it down?
Answer: You can sprinkle a small amount of water on the seat or wipe it with a wet cloth.
As the water evaporates, it absorbs heat from the seat and the surroundings. This produces a cooling effect, making the seat comfortable to sit on.
Another simple way is to park the vehicle in the shade whenever possible to prevent it from becoming too hot.
Chapter Overview
This chapter discusses the three states of water; solid (ice), liquid (water) and gas (water vapour). It explains that ice, water and water vapour are different forms of the same substance. Ice has a fixed shape, liquid water flows and takes the shape of its container, while water vapour spreads out to fill the available space. The chapter also explains that other substances such as wax and ghee can also change their state when heated or cooled.
The chapter explains the different processes through which water changes from one state to another. Melting is the process by which ice changes into water, while freezing is the process by which water changes into ice. Students also learn that evaporation is the process by which water changes into water vapour and can take place at any temperature. This is different from boiling, which occurs only at the boiling point and takes place throughout the liquid. It includes daily examples such as drying clothes, a wet floor drying and sweat evaporating from the skin, which helps students understand these concepts.
Students also learn about the four factors that affect the rate of evaporation; temperature, surface area, air movement and humidity. The chapter explains that evaporation causes a cooling effect because it absorbs heat from the surroundings. This is why sweating cools the body and why earthen pots keep water cool. It also discusses condensation, the process by which water vapour changes back into liquid water when it comes in contact with a cold surface. Water droplets on the outside of a cold glass and dew on leaves are common examples of condensation.
The chapter explains how clouds are formed when water vapour rises, cools and condenses around tiny dust particles in the atmosphere. Students also learn about the complete water cycle, which consists of evaporation, condensation, precipitation and collection. The chapter explains that the Sun provides the energy that drives the water cycle and helps maintain the continuous movement of water in nature. It explains why natural grass feels cooler than plastic grass using the concept of transpiration and its cooling effect.
Topics Covered in This Chapter
- The disappearance of water puddles.
- The three states of water: solid (ice), liquid (water) and gas (water vapour).
- Changes of state: melting, freezing and evaporation.
- The difference between evaporation and boiling.
- Factors affecting the rate of evaporation: humidity and the cooling effect of evaporation, with examples.
- Condensation and its examples.
- Cloud formation and its experiment.
- The Water Cycle.
- Transpiration.
- Water conservation.
How to Prepare for This Chapter Using NCERT Solutions?
Start by thinking about three everyday observations before you read the chapter: why do wet clothes dry faster in the sun and wind than in the shade and still air, why does a cold glass get wet on the outside and why does an earthen pot keep water cool? This will help you understand the core concepts of the chapter. Next, learn the four factors affecting evaporation. Temperature, surface area, air movement and humidity are the factors and for each one, you should also know what the factor is and exactly how it affects the rate. These are often asked as fill in the blanks or reasoning-type short-answer questions.
For the difference between evaporation and boiling, you must always remember the two key differences: evaporation happens at all temperatures, while boiling happens only at 100 °C, and evaporation is a surface process, while boiling happens throughout the entire body of the liquid. For condensation, the most important thing to remember is the source of the water droplets on a cold glass. They come from water vapour in the surrounding air, not from inside the glass. The water cycle diagram is a standard five-mark question that is often asked. Practice drawing and labelling it with all four stages: evaporation, condensation, precipitation and collection. Also, include the role of the Sun as the energy source for evaporation.
After completing the chapter, practice all NCERT textbook questions yourself before checking the solutions. For CBSE Board Class 6 A Journey through States of Water MCQs, the most frequently asked questions are the definitions and examples of evaporation, condensation and precipitation; the factors affecting evaporation; the cooling effect and its explanation; the source of water droplets on a cold glass; why natural grass is cooler than plastic grass; the stages of the water cycle and the definition of humidity.
Common Mistakes to Avoid
Forgetting the Factors Affecting Evaporation: Learn the four factors affecting evaporation: temperature, surface area, air movement and humidity. Understand how each factor affects the rate of evaporation instead of just memorising their names. Questions often use everyday examples, such as why clothes dry faster on a sunny, windy day or why water in a plate evaporates faster than water in a bottle.
Confusing Evaporation and Boiling: A very common mistake is treating evaporation and boiling as the same process. Remember that evaporation occurs at all temperatures and only from the surface of a liquid, whereas boiling occurs only at 100 °C and takes place throughout the entire body of the liquid. Evaporation is also a slow, gradual process, while boiling is rapid. Both convert liquid water into vapour, but through entirely different processes.
Forgetting Parts of the Water Cycle: When drawing or explaining the water cycle, include all four stages: evaporation, condensation, precipitation and collection. Also include the Sun as the energy source that drives the water cycle. For detailed answers, you should also include transpiration, the process by which plants release water vapour through their leaves.
Confusing Condensation: The water droplets that form on the outside of a cold glass come from water vapour present in the surrounding air, not from the liquid inside the glass. The cold surface of the glass causes the water vapour in the surrounding air to condense into liquid droplets. The water level inside the glass does not decrease. This is one of the most frequently asked questions in school exams.
Forgetting Why Evaporation Causes Cooling: Students often remember that evaporation causes cooling but forget the reason. Evaporation absorbs heat from the surrounding surface as liquid water changes into vapour, causing the surface to cool. You must explain this using examples such as an earthen pot keeping water cool, sweating cooling the body, a wet cloth cooling a hot two-wheeler seat and natural grass feeling cooler than plastic grass.
