Important Questions Class 6 Science Chapter 6

Important Questions Class 6 Science Chapter 6 – Changes Around Us

Science is one of the most important channels of knowledge. It is valued by society because applying scientific knowledge helps satisfy many basic human needs and improve living standards. It also deals with the properties, composition, and structure of substances, their transformation, and the energy released or absorbed during these processes. 

Changes Around Us is the sixth chapter in the Class 6 Science syllabus. Change is a process in which one or more substances are altered into one or more new substances. It is also defined as any alteration of a substance’s original shape, size and state. For example, when the ice melts, it changes into water. Therefore it turns from solid to liquid. Changes are very random and uncertain phenomena. Those changes can be either reversible or irreversible. A reversible change is a chemical change where no materials are created, and the original material can be recovered. The change in which the substance cannot be brought back to its original state is called an irreversible change.

Extramarks is an online learning platform that offers high-quality self-study modules and live classes from some of the best subject teachers in the industry. Our education content is constantly reviewed and improved to make the whole process of learning for the students as effectively as possible. Extramarks provides comprehensive study materials such as NCERT solutions, CBSE revision notes, CBSE sample papers, CBSE past years’ question papers and more. 

Our team understands the importance of problem-solving for Science subjects. Students can refer to our question bank of Important Questions Class 6 Science Chapter 6. This questionnaire is prepared by referring to the latest CBSE syllabus and past year’s exam papers to select questions that cover a variety of topics from the chapter ‘Change around us’. It also helps students to categorise questions into different difficulty levels. By solving these Important Questions Class 6 Science Chapter 6, students can understand the scoring pattern and prepare their exam strategy and timetable accordingly. Regularly solving questions will help you enhance your exam performance, and strengthen your weak areas which will help you reduce your mistakes. Overall this will boost your confidence and get you more marks in your exams.

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Important Questions Class 6 Science Chapter 6 – With Solutions

One of the most common methods for familiarising yourself with an examination pattern is to solve Important Questions Class 6 Science Chapter 6. The solutions given to these important questions are prepared by experienced Science teachers. Each question comes with a step-by-step guided solution that will help you revise the chapter concepts while solving these questions.

Our question bank of Science Class 6 Chapter 6 Important Questions and related solutions help you become familiar with the examination structure. So practising questions from our question bank is one of the most effective ways to prepare for an examination. 

Listed below are a few questions from our questionnaire of Important Questions Class 6 Science Chapter 6. Students can register on Extramarks website to get full access to these questions and solutions.

Question 1. You accidentally dropped your favourite toy and cracked it. This is a change you did not need. Can this change be reversed?

Answer 1: No, this change cannot be reversed.

Question 2. A drawing sheet changes when you draw a picture on it. Can you reverse this change?

Answer 2: No, once a picture has been drawn on a drawing page using paint, oil, or water, it cannot be replaced. We can reverse the change if a soft pencil is used to draw the picture.

Question 3. A thick coating of a paste of Plaster of Paris (POP) is applied over the dressing on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. Can the change in Plaster of Paris (POP) be reversed?

Answer 3: No, the change in Plaster of Paris cannot be reversed since it is a chemical change.

Question 4. Give two examples of reversible changes.

Answer 4: 

• Melting of ice into water.
• Folding a paper.

Question 5. Why does a blacksmith heat the metal rim to fix it on a cartwheel?

Answer 5: A blacksmith heats the metal rim to fix it onto a cartwheel because a metal rim is made slightly smaller. The rim swells when heated and fits the wheel. The rim then contracts as it cools and snugly fits onto the wheel.

Question 6. Classify the following into slow and fast changes:

(i) Spinning of a top

(ii) Formation of day and night

(iii) Formation of curd from milk

(iv) Change of seasons

(v) Making curd from milk by adding lemon juice.

Answer 6 :

Question 7. What is a physical change? Explain with an example.

Answer 7:  Physical change is when the composition of matter is altered but not changed into a different substance. It does not produce a new substance. Examples: Melting an ice cube, boiling water, mixing sand and water, breaking a glass etc.

Question 8. How does curd get prepared? Is this change reversible?

Answer 8: Warm milk is infused with a small amount of curd. The milk is churned and left undisturbed for a few hours in a warm location. The milk turns into curd after a little while.

Curd cannot be converted back into milk once the curd has been produced. This alteration is therefore, irreversible (cannot be undone).

Question 9. Salt can be segregated from its solution (salt dissolved in water) because

1. a) Adding salt to water is a permanent change.
2. b) Adding salt to water is a change that can be reversed by heating and melting salt.
3. c) Adding salt to water is a change that cannot be reversed.
4. d) Mixing salt in water is a change that evaporation can reverse.

Answer 9 : (d)

Question 10.

Rolling of chapati and baking it are the changes that

(a) cannot be reversed

(b) can be reversed

(c) cannot be reversed and can be reversed, respectively

(d) can be reversed and cannot be reversed, respectively.

Answer 10: (d) Chapati rolling is a physically reversible alteration because the properties of kneaded flour remain unchanged. The chapati cannot be reversed once it is baked.

Question 11. A piece of iron is heated till it becomes red-hot. It then becomes soft and is beaten to the desired shape. What kind of changes are observed in this process-reversible or irreversible?

Answer 11: Iron can be beaten into the desired shape after heating. Because the desired shape may be restored by heating and beating the object once more, the change is reversible.

Question 12. The tearing of paper is said to be a change that cannot be reversed. What about paper recycling?

Answer 12: The quality, colour and texture of recycled paper vary, and we end up with a different kind of paper than the original; hence recycling cannot be categorised as a reversible change.

Question 13. Changing a bud into a flower is a change that cannot be reversed. Give four more such examples.

Answer 13: Examples of irreversible change:

• Rusting of iron
• Cooking of food
• Ripening of fruits
• Falling leaves from a tree

Question 14. Choose the change that can be reversed from the following.

(a) Cutting off trees

(b) Melting of ghee

(c) Burning of a candle

(d) Blooming of a flower

Answer 14:

(b): Ghee that has melted can be refrozen. So it is a reversible change. Cutting trees, burning candles, and blooming flowers cannot be reversed.

Question 15. State the list of changes caused due to heating. 

Answer 15: The changes caused due to heating are:

• Expansion
• Combustion
• Change in state

Question 16. List the characteristics of physical change.

Answer 16:

• They are usually reversible.
• No new substance is formed.
• The chemical characteristics of a substance remains the same.
• Change in colour, shape, size and state.
• No energy is liberated.

Question 17.

A new bottle of pickles had been purchased by Paheli from the market. To taste it, She made an effort to open the metal cap but it was unsuccessful. The upper end of the bottle was then submerged in a bowl of hot water for five minutes. She could easily open the bottle now. Can you give the reason for this?

Answer 17 : The metal cap is readily removed after being submerged in hot water since it expands in size.

Question 18.

Which of the following changes are not reversed?

(a) Folding a piece of paper to make a toy aeroplane

(b) Blowing of a balloon

(c) Baking a cake in an oven

(d) Rolling a ball of dough to make roti 

(e) Drying a wet cloth

(f) Making biogas from cow dung

(g) Burning of a candle

Answer 18:

(c) Baking a cake in an oven.

(f) Making biogas from cow dung.

(g) Burning of a candle.

Question 19. State whether the burning of a piece of paper is a reversible or an irreversible change.

Answer 19: A piece of paper turns into smoke and ash when we burn it. Ash and smoke cannot be combined to create the original sheet of paper. Thus the burning of paper is an irreversible change.

Question 20. Cracker explosion is a chemical change. Explain.

Answer 20: A cracker explosion is a chemical change because the explosive reactants are converted into gaseous byproducts along with heat, light, and sound that cannot be reversed. It is therefore, a chemical alteration.

Question 21. What are the various forms of changes noticed?

Answer 21:  The different forms of changes noticed are:

• Change in shape
• Change in colour
• Change in size
• Change in state
• Change in direction

Question 22: Is printing a reversible or an irreversible change?

Answer 22: Since we cannot separate and collect the printing ink after printing, printing results in an irreversible change.

Question 23. Can we reverse the following changes? If yes, suggest the name of the process.

(a) Water into water vapour

(b) Water vapour into water

(c) Ice into water

(d) Curd into milk.

Answer 23:

(a) Water into water vapour – Yes.

 Water vapour can be converted to water by the condensation process.

(b) Water vapour into the water – Yes.

 By the process of evaporation, water can be converted to water vapour.

(c) Ice into the water – Yes.

Water can be converted to the ice by freezing.

(d) Curd into milk is an irreversible process.

Benefits of Solving Important Questions Class 6 Science Chapter 6

Solving Important Questions Class 6 Science Chapter 6 is a good way to practice, evaluate, identify and improve the study process. We recommend students register on the Extramarks website to get access to our comprehensive study materials.

Below are a few of the benefits that students will get by referring to our Important Questions Class 6 Science Chapter 6:

• By referring to a variety of questions, students will understand the structure of the questions that are likely to be asked in exams. This familiarity will help students score better in exams.
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• Solving Science Class 6 Chapter 6 important questions also help students practice good time management strategies required to ace an examination and finish a question well within the given time limitations.
• Class 6 Science Chapter 6 Important Questions can be used as a great self-evaluation tool to track the test preparation progress. Students can practise Important Questions Class 6 Science Chapter 6 and compare their current performance to past attempts to determine where they specialise and where they fall short.

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