Updated 2022 - NCERT Solutions for Class 6 Science Chapter 6 - Changes Around Us.

NCERT Solutions for Class 6 Science Chapter 6 - Changes Around Us Includes all the NCERT Solutions for Class 6 Science Chapter 6 - Changes Around Us. These NCERT Solutions for Class 6 Science Chapter 6 - Changes Around Us Contains questions their answers and solutions with detailed Explanation. If you are a student of Class 6 and use NCERT Text book to study then these NCERT Solutions for Class 6 Science Chapter 6 - Changes Around Us are very useful for you to study well. On this page you not only get NCERT Solutions for Class 6 Science Chapter 6 - Changes Around Us but you also get some very important extra questions of this chapter. On this page you find NCERT Solutions for Class 6 Science Chapter 6 - Changes Around Us, Class 6 science chapter 6 question answer, Questions based on Chapter understanding, Some important definitions, Short answer Questions, Long answer Questions and some important Value based questions. For a better understanding of this chapter, you should also see Class 6 Science Chapter 6 Notes (pdf) based on NCERT for Class 6 Science Chapter 6 - Changes Around Us.

- CHAPTER EXPLANATION -

MSEducator.in - Video Explanation of Class 6 Science Chapter 6 - Changes Around Us.

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- CHAPTER OVERVIEW -

These Topics are covered in NCERT Class 6 Science Chapter 6 - Changes Around Us.

# Physical and Chemical Changes.

# Reversible and Irreversible Change.

# Periodic and Non-periodic Change.

# Desirable and Undesirable Change.

# Slow and Fast Change.

# Expansion and Contraction.

# Evaporation and Condensation.

# Freezing, Melting and Burning.

- CHAPTER NOTES -

Here you get The CHAPTER NOTES (pdf) For Class 6 Science Chapter 6 - Changes Around Us. These notes are completely based on NCERT Class 6 Science Chapter 6 - Changes Around Us. These notes contains detailed explanation of NCERT Class 6 Science Chapter 6 - Changes Around Us. I suggest you to go through these Notes to strengthen you understanding about this Class 6 Science Chapter 6 - Changes Around Us.

- NCERT SOLUTIONS -

These NCERT Solutions for Class 6 Science Chapter 6 - Changes Around Us Contains Answers and solutions for questions given in the Class 6 Science Chapter 6 NCERT Text Book Back Exercises. Here you get questions their answers and solutions with detailed Explanation of NCERT Class 6 Science Chapter 6 - Changes Around Us which helps you to understand the chapter with more clarity.

NCERT Solutions for Class 6 Science Chapter 6 - Changes Around Us.

NCERT BACK EXERCISES SOLUTIONS

Q1. To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?

Ans. Yes. The length of the dress can again be increased by unfolding it. Hence, this change can be reversed.

Q2. You accidentally drop your favourite toy and break it. This is a change you did not want. Can this change be reversed?

Ans. No. This change cannot be reversed. We cannot join the broken parts of the toy.

Q3. Some changes are listed in the following table. For each change, write in the blank column

whether the change can be reversed or not.

MSEducator.in - NCERT Q3 of Class 6 Science Chapter 6 - Changes Around Us

Correct Answer :

MSEducator.in - NCERT Q3 Solution of Class 6 Science Chapter 6 - Changes Around Us

Q4. A drawing sheet changes when you draw a picture on it. Can you reverse this change?

Ans. We can reverse this change if the picture is made by pencil on drawing sheet. We can't reverse this change if the picture is made by pen, oil colour or sketch pen.

Q5. Give example to explain the difference between changes that can or cannot be reversed.

Ans. To explain the differences between changes that can or cannot be reversed, some examples are given below:

(a) If we inflate a balloon, the size and shape of the balloon undergoes a change. However, the original size and shape of the balloon can be obtained back by allowing the air to escape from the balloon. This means that the change that occurs by inflating a balloon can be reversed. But, if the balloon bursts after being inflated, then its original size and shape cannot be obtained back. Thus, in this case, the change cannot be reversed.

(b) If we fold a piece of paper, then the shape and size of the paper undergoes a change. In this case, the original shape and size of the original paper can be obtained back. Thus, this change can be reversed. However, if we cut the piece of paper, the change in the shape and size of the paper cannot be reversed.

(c) The shape of rubber band can be changed by stretching which can be reversed.

Q6. A thick coating of paste of Plaster of Paris is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilized. Can the change in POP be reversed?

Ans. No, the change in plaster of Paris cannot be reversed as it became hard on drying and new product is formed.

Q7. A bag of cement lying in the open gets wet due to rain during the night. The next day, the sun shines brightly. Do you think the changes that have occurred in the cement can be reversed?

Ans. In this case, the changes cannot be reversed. This is because the cement that hardens up after getting wet cannot be obtained back. It is an irreversible chemical change.

Extra Questions for Class 6 Science Chapter 6 - Changes Around Us.

- EXTRA QUESTIONS -

Here you get Some Extra questions regarding NCERT Class 6 Science Chapter 6 - Changes Around Us. In which you get Definition of some terms talked about in NCERT Class 6 Science Chapter 6 - Changes Around Us. You also get some short questions and long questions regarding NCERT Class 6 Science Chapter 6 - Changes Around Us And Some Value Based Questions regarding NCERT Class 6 Science Chapter 6 - Changes Around Us. If you prepare all these questions for your exams, then you will definitely get good marks in your upcoming examinations.

NOW let's see some Extra Questions for Class 6 Science Chapter 6 - Changes Around Us.

# Define The Following Terms :

Q. Define physical change.

Ans. The changes in which only physical properties of substances are changed and no new substance is formed is called physical change. It is a reversible change.

E.g. Boiling and freezing of water.

Q. Define chemical change.

Ans. The changes in which new substance with new chemical properties are formed are called chemical changes. It is a irreversible change.

E.g. Formation of curd and paneer from milk.

Q. Define Reversible change.

Ans. Reversible change is a change which can be reversed by one or more methods. Usually, there is a change in physical properties, shape and size of the material. Mostly a new substance is not formed in a reversible change.

E.g. Folding of paper, stretching of rubber band, etc.

Q. Define Irreversible change.

Ans. The change, which is permanent and cannot be undone by any physical or chemical means is called an irreversible change. Formation of new substance is involved in this change.

E.g. Formation of curd from milk is an irreversible change as we cannot get back the milk out of curd.

Q. Define periodic Changes.

Ans. Changes which are repeated after regular intervals are called periodic changes.

E.g. Day and night, changing phases of the moon, beating of heart, etc.

Q. Define Non-periodic changes.

Ans. Changes which do not repeated after regular intervals are called non- periodic changes.

E.g. Rainfall, snowfall, volcanic eruption, etc.

Q. Define Desirable change.

Ans. Desirable Changes are those changes which are desired to occur that is, we want them to take place are known as desirable changes. Examples: ripening of fruits, germination of seeds etc.

Q. Define Undesirable change.

Ans. Undesirable change are those changes which we do not want to take place are called undesirable changes. Example: Rain causing destruction by floods, souring of milk, spoiling of food, etc.

Q. Define Slow change.

Ans. The changes which take place in a long period of time are called slow changes.

E.g. Rusting of iron, ripening of fruits, growing of trees.

Q. Define Fast changes.

Ans. The changes which take place in a short period of time are called fast changes.

E.g. Burning of paper, stretching of rubber band, blowing of balloons.

Q. Define Expansion.

Ans. The act or process of expanding or the increase in volume of any substance is called Expansion. When the temperature increases, the particle of a substance expands or becomes loose. When this happens, the material is said to undergo expansion.

Q. Define Contraction.

Ans. The act or process of contracting or the Decrease in volume of any substance is called Contraction. When the temperature decreases, the particles of substance contracts or becomes tight. When this happens, the material is said to undergo contraction.

Extra Questions for Class 6 Science Chapter 6 - Changes Around Us.

# Very Short Answer Type Questions :

Q. Name the changes that lead to the formation of new substances.

Ans. Chemical changes.

Q. If the removal of the cause of change leads to regain the original situation, then the change is known as.

Ans. Reversible change.

Q. Name the change occur in Burning of wood in a chullha.

Ans. Irreversible

Q. Name the process by which liquid changes into vapour by heating.

Ans. Evaporation

Q. Name the original substance that take part in a reaction.

Ans. Reactant

Q. Name the process of converting solids into gaseous form.

Ans. Sublimation

Q. Name the change which occurs on heating but can be reversed.

Ans. Heating of an iron rod.

Q. Name the change which occurs on heating but cannot be reversed.

Ans. Baking of chapati.

Q. Change which occurs on cooling but can be reversed.

Ans. Formation of ice from water.

Q. Change which occurs on mixing two substances, but can be reversed.

Ans. Formation of salt solution.

Q. Change which occurs on mixing two substances, but cannot be reversed.

Ans. Mixing of cement and water.

Q. Give one examples of slow changes.

Ans. Growing plants.

Q. Give one examples of fast changes.

Ans. Blowing a balloon.

Q. Give one examples of reversible changes.

Ans. Heating of milk.

Q. Give one examples of irreversible changes.

Ans. Cooking of food.

Q. Deforestation is an irreversible or reversible change?

Ans. It is an irreversible change.

Extra Questions for Class 6 Science Chapter 6 - Changes Around Us.

# Short Answer Type Questions :

Q. What is a physical change? Explain with example.

Ans. The changes in which only physical properties of substances are changed and no new substance is formed is called physical change. It is a reversible change.

E.g. Boiling and freezing of water.

Q. What is a chemical change? Explain with example.

Ans. The changes in which new substance with new chemical properties are formed are called chemical changes. It is a irreversible change.

E.g. Formation of curd and paneer from milk.

Q. What are periodic and non-periodic changes? Give examples.

Ans. Changes which are repeated after regular intervals are called periodic changes. Day and night, changing phases of the moon, beating of heart, etc. are examples of periodic changes. While, changes which do not repeated after regular intervals are called non- periodic changes. Rainfall, snowfall, volcanic eruption, etc. are the examples of non-periodic changes.

Q. Explain desirable and undesirable changes with examples.

Ans. Desirable Changes are those changes which are desired to occur that is, we want them to take place are known as desirable changes. Examples: ripening of fruits, germination of seeds etc. Undesirable change are those changes which we do not want to take place are called undesirable changes. Example: Rain causing destruction by floods, souring of milk, spoiling of food, etc.

Q. What are slow and fast changes? Give examples.

Ans. The changes which take place in a long period of time are called slow changes whereas that changes which take place in a short period of time are called fast changes.

E.g.

(a) Rusting of iron, ripening of fruits, growing of trees are slow changes.

(b) Burning of paper, stretching of rubber band, blowing of balloons, bursting of crackers are fast changes.

Q. Classify the following into slow and fast changes:

(a) Spinning of top

(b) Formation of day and night

(c) Formation of curd from milk

(d) Change of season

(e) Making paneer from milk by adding lemon juice.

Ans.

(a) Fast change

(b) Slow change

(c) Slow change

(d) Slow change

(e) Fast change.

Q. Name two ways by which a change can be made in a substance.

Ans.

(a) Change in temperature

(b) Change in pressure

Q. State the list of changes caused due to heating.

Ans. The changes caused due to heating are :

(a) Change in size (Expands)

(b) Change in state (Solid to Liquid to Gas)

Q. A piece of iron is heated till it becomes red-hot. It then becomes soft and is beaten into a desired shape. What types of changes are observed in this process? Reversible or irreversible?

Ans. A blacksmith first heats a piece of iron till it becomes red hot. It then becomes soft and can be beaten into desired shape. Iron when heated and beaten it forms some shape and again heated it regain initial iron. Thus, this change is a reversible change.

Q. Explain how a metal rim slightly smaller than a wooden wheel can be fixed on it.

Ans. The metal rim is always made slightly smaller than the wooden wheel. Firstly the metal rim is heated; on heating, the rim expands and fits onto the wheel. Then, cold water is poured over the rim. Due to cooling, rim contracts and fits tightly over the wheel.

Q. Does, like all other liquids, water expand on heating and contract on cooling?

Ans. No, water is an exception. Water contracts on cooling till 4°C but expands when cooled further down from 4°C to 0°C. You must have seen water vapour comes out of Ice.

Q. Parul had bought a new bottle of pickle from the market. She tried to open the metal cap to taste it but could not do so. She then took a bowl of hot water and immersed the upper end of the bottle in it for five minutes. She could easily open the bottle now. Can you give the reason for this ?

Ans. On immersing in hot water, the metal cap expands in size hence it can be removed easily.

Q. Can we reverse the following changes? If yes, suggest the name of the method.

(a) Water into water vapour

(b) Water vapour into water.

(c) Ice into water.

(d) Curd into milk.

Ans.

(a) Yes, condensation

(b) Yes, evaporation

(c) Yes, freezing

(d) Not possible

Q. Which of the following changes cannot be reversed?

(a) Blowing of a balloon

(b) Folding a paper to make a paper-plane.

(c) Rolling a ball of dough to make roti

(d) Baking cake in an oven

(e) Drying a wet cloth

(f) Making biogas from cow dung

(g) Burning of a candle

Ans.

(d) Baking cake in an oven

(f) Making biogas from cow dung

(g) Burning of a candle

Q. Conversion of ice into water and water into ice is an example of change which can be reversed. Give four more examples where you can say that the changes can be reversed.

Ans.

(a) Melting of wax

(b) Folding of a paper

(c) Knitting of a sweater

(d) Blowing of Balloon.

Q. Change of a bud into a flower is a change which cannot be reversed. Give four more such example.

Ans.

(a) Milk into curd

(b) Burning of wood

(c) Ripening of fruits

(d) Digestion of food

Q. Can deforestation be considered as a reversible change?

Ans. No, deforestation can’t be considered as a reversible change because no same tree can be planted after falling down or cutting.

Q. Formation of clouds is a physical change. Explain.

Ans. Formation of clouds is a physical change as it is a phase of natural water cycle, transformation of water from liquid to gas and then gas to liquid. Hence, the property of water never changes in any form.

Q. Explosion of a cracker is a chemical change. Explain.

Ans. Explosion of a cracker is a chemical change because the explosive reactants are transformed into gaseous products along with heat, light and sound which cannot be reversed. Hence, it is a chemical change.

Q. Why do we keep vegetables or fruits in refrigerator?

Ans. We refrigerate fruits to keep away bacteria & yeasts, as they starts growing when they get favorable warm temperature. These microorganisms can spoil fruits which is an irreversible and undesirable change.

Q. What kind of changes occur in a burning candle? Give reasons.

Ans. When the candle burns, it's wax melts and no new substance is formed as the molten wax can be solidified again and made into a candle, So it is a reversible change. While, on burning, the oxygen in the air reacts and forms carbon dioxide, A new substance is formed. So, it is a chemical change.

Q. Name the three states in which water exist. How the conversion takes place from one state to the other?

Ans. Water has 3 physical states. Water is the only substance on Earth that naturally occurs in three physical states which are solid, liquid, and gas. Water can change from one state to another depending on temperature and atmospheric pressure applied to it.

Q. Why does the level of mercury rises up when it comes in contact with hot objects?

Ans. Mercury is a metal which is liquid at room temperature, but when heated it gets expanded. Hence, its level rises in the capillary when comes in contact with a hot object.

Q. Boojho’s sister broke a white dove, a symbol of peace, made of Plaster of Paris (POP). Boojho tried to reconstruct the toy by making a powder of the broken pieces and then making a paste by mixing water. Will he be successful in his effort? Justify your answer.

Ans. Boojho will not be successful, because making of anything from Cement or Plaster of Paris (POP) is a change that cannot be reversed.

Q. Tearing of paper is said to be a change that cannot be reversed. What about paper recycling?

Ans. We do get the paper on paper recycling but it is not the same original paper that we get. The colour and texture of the paper changes.

Q. A potter working on his wheel shaped a lump of clay into a pot. He then baked the pot in an oven. Do these two acts lead to the same kind of changes or different? Give your opinion and justify your answer.

Ans. These two act are of different kinds as formation of pot from clay can be reversed while Baking the pot in an oven cannot be reversed.

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

Ans. No, we cannot get fresh drawing sheet once a picture is drawn on it with oil and water color. However, we can reverse the change, if soft pencil is used to draw the picture.

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

Ans No, the change in POP cannot be reversed since it is a chemical change.

Q. A bag of cement lying in the open gets wet due to rain during the night. The next day the sun shines brightly. Do you think the changes, which have occurred in the cement, could be reversed?

Ans. No, these are irreversible chemical changes.

Q. How does curd being set? Is this change reversible?

Ans. A small quantity of curd is added to warm milk. The milk is stirred and is set aside undisturbed at a warm place for some hours. After some hours, the milk changes into curd. Curd formed from milk cannot be changed into milk again. So, this an irreversible change.

Extra Questions for Class 6 Science Chapter 6 - Changes Around Us.

# Long Answer Type Questions :

Q. Give an example from daily life where expansion of metal by heating is used. Explain.

Ans. Fixing of wooden handles in iron blade in agricultural tools. The iron blade of these tools has a ring by which the wooden handle is fixed. Normally, the ring is slightly smaller in size than the wooden handle. To fix the handle, the ring is heated and it becomes slightly larger in size (expands). Now, the handle easily fits into the blade by using the ring. When the ring cools down, it contracts and fits tightly onto the handle.

Q. What is the difference between following changes:

(a) Rolling a roti from dough.

(b) Baking of a roti.

Ans.

(a) The rolling of roti out of dough is a physical change as it can be reversed. We can convert this rolled roti back into the ball of dough. Thus, it is an reversible and physical change.

(b) Baking of roti is a chemical change as it can not be reversed. Baked roti cannot be changed back into the original ball of dough. Thus, it is an irreversible and chemical change.

Q. List any three changes that take place in the presence of sunlight?

Ans. Changes that take place in presence of sunlight are :

(a) Photosynthesis : The process by which green plant prepare their own food in presence of sunlight.

(b) Ozone Formation : Formation of Ozone is done in the presence of sunlight.

(c) Vitamin D synthesis : Vitamin D is synthesized in our skin, in the presence of sunlight.

(d) Evaporation : Conversion of water into water vapour.

Q. Paheli mixed flour and water and

(a) made a dough,

(b) rolled the dough to make a chapati,

(c) baked the chapati on a pan,

(d) dried the chapati and ground it in a grinder to make powder.

Identify the changes (a) to (d) as the changes that can be reversed or that cannot be reversed.

Ans.

Changes that can be reversed are :

(b) rolled the dough to make a chapati.

Changes that cannot be reversed are :

(a) made a dough,

(c) baked the chapati on a pan,

(d) dried the chapati and ground it in a grinder to make powder.

Q. It was Paheli’s birthday, her brother Simba was helping her to decorate the house for the birthday party and their parents were also busy making other arrangements. Following were the activities going on at Paheli’s home:

(a) Simba blew balloons and put them on the wall.

(b) Some of the balloons got burst.

(c) Paheli cut colourful strips of paper and put them on the wall with the help of tape.

(d) She also made some flowers by origami (paper folding) to decorate the house.

(e) Her father made dough balls.

(f) Mother rolled the dough balls to make puries.

(g) Mother heated oil in a pan.

(h) Father fried the puries in hot oil.

Identify the activities at Paheli’s home as those that can be reversed and those which cannot be reversed.

Ans.

Activities that can be reversed are :

(a) Simba blew balloons and put them on the wall.

(d) She also made some flowers by origami (paper folding) to decorate the house.

(e) Her father made dough balls.

(f) Mother rolled the dough balls to make puries.

(g) Mother heated oil in a pan.

Activities that can not be reversed are :

(b) Some of the balloons got burst.

(c) Paheli cut colourful strips of paper and put them on the wall with the help of tape.

(h) Father fried the puries in hot oil.

We hope that the given material for Class 6 Science Chapter 6 - Changes Around Us will help you to understand the concepts with more clarity. But, If you have any query regarding Class 6 Science Chapter 6 - Changes Around Us then just ask your doubts in the section given below.