Which of the following can be considered as a fast change?
- AGrowth of child.
- BGermination of seed.
- ✓Bursting of cracker.
- DCooking of food.
Answer: C.
View full solution →Question types
Changes Around Us question types
379 questions across 9 question groups — pick any mix to generate a Science paper with step-by-step answer keys.
379
Questions
9
Question groups
5
Question types
01
[1 Marks Each] M.C.Q.
248 Q→02Assertion (A) & Reason (B) MCQ
3 Q→03[1 Marks Each] Blanks
20 Q→04True Or False.[1 Marks Each]
19 Q→05[1 Marks Each] QUE - ANS
48 Q→06[3 Marks Each] QUE-ANS
7 Q→07[5 Marks Each] QUE-ANS
6 Q→08case /data -based (4 Marks)
5 Q→09Answer The Following Questions In Short.[2 Marks Each]
23 Q→Sample Questions
Changes Around Us questions
One sample from each question group in this chapter. Select any group above to see the full set with answer keys.
Which of these is not a physical change?
- ASulphur dissolved in carbon disulphide.
- BResin dissolved in alcohol.
- ✓The fermentation of cane juice.
- DThe glowing of an electric bulb.
Answer: C.
View full solution →Heating of wax in a pan is a:
- ✓Reversible change.
- BIrreversible change.
- CPermanent change.
- DNone of these.
Answer: A.
View full solution →The new substance formed during or after a chemical reaction is:
- ACatalyst.
- BInhibitor.
- ✓Product.
- DReactant.
Answer: C.
View full solution →Which among the following is not an example of a reversible change?
- ADissolving sugar in water.
- ✓Changing of wheat to flour.
- CFolding up of a paper.
- DMelting of coal tar.
Answer: B.
View full solution →Directions: The questions in this segment consists of two statements, one labelled as "Assertion $A"$ and the other labelled as "Reason $R"$. You are to examine these two statements carefully and decide if the Assertion $A$ and Reason $R$ are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below.
Assertion A: The process of conversion of liquid water to its vapours by heating the liquid is called boiling.
Reason R: The process of conversion of water vapours to liquid by cooling the vapours is called condensation.
Assertion A: The process of conversion of liquid water to its vapours by heating the liquid is called boiling.
Reason R: The process of conversion of water vapours to liquid by cooling the vapours is called condensation.
- ABoth $A$ and $R$ are true and $R$ is the correct explanation of $A$
- ✓Both $A$ and $R$ are true but $R$ is not the correct explanation of $A$
- C$A$ is true but $R$ is false
- D$A$ is false but $R$ is true
Answer: B.
View full solution →Directions: The questions in this segment consists of two statements, one labelled as "Assertion $A"$ and the other labelled as "Reason $R"$. You are to examine these two statements carefully and decide if the Assertion $A$ and Reason $R$ are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below.
Assertion A: Burning of paper is a physical change.
Reason R: The products formed on burning of paper cannot be easily converted back to paper.
Assertion A: Burning of paper is a physical change.
Reason R: The products formed on burning of paper cannot be easily converted back to paper.
- ABoth $A$ and $R$ are true and $R$ is the correct explanation of $A$
- BBoth $A$ and $R$ are true but $R$ is not the correct explanation of $A$
- C$A$ is true but $R$ is false
- ✓$A$ is false but $R$ is true
Answer: D.
View full solution →Directions: The questions in this segment consists of two statements, one labelled as "Assertion $A"$ and the other labelled as "Reason $R"$. You are to examine these two statements carefully and decide if the Assertion $A$ and Reason $R$ are individually true and if so, whether the reason is a correct explanation of the assertion. Select your answers to these items using codes given below.
Assertion A: The explosion of a fire cracker sis a physical changes.
Reason R: A physical change is a reversible change.
Assertion A: The explosion of a fire cracker sis a physical changes.
Reason R: A physical change is a reversible change.
- ABoth $A$ and $R$ are true and $R$ is the correct explanation of $A$
- BBoth $A$ and $R$ are true but $R$ is not the correct explanation of $A$
- C$A$ is true but $R$ is false
- ✓$A$ is false but $R$ is true
Answer: D.
View full solution →Water vapour changes into $.........$ when it is cooled.
View full solution →Fill in the blanks with appropriate words:
$.........$ is a reversible change.
View full solution →$.........$ is a reversible change.
Fill in the blanks with appropriate words:
Changes that lead to the formation of new substances are called $.........$
View full solution →Changes that lead to the formation of new substances are called $.........$
Conversion of water vapour into liquid water is a $.........$ change.
View full solution →When metal ring is heated, it $.........$
View full solution →Eruption of a volcano is a reversible change. True/ False
Formation of clouds is an irreversible change. True/ False
Cooking of rice is a physical change. True/ False
Pressure is equal to the force per unit second. True/ False
Cooling the hot milk is a reversible change. True/ False.
Can you obtain wood from sawdust?
How can a change occur in a substance?
Is steaming of idli batter to make idli a reversible change? Give reasons to support your answer.
Cold milk is heated and it becomes hot. Which type of change it is?
You accidentally drop your favourite toy and break it. This is a change you did not want. Can this change be reversed?
Look at which shows three situation:
Which of these shows a reversible change and why?
- A burning candle.
- An extinguished candle.
- Melting wax.
Which of these shows a reversible change and why?
Which of the following changes cannot be reversed?
- Blowing of a balloon.
- Folding a paper to make a toy aeroplane.
- Rolling a ball of dough to make roti.
- Baking cake in an oven.
- Drying a wet cloth.
- Making biogas from cow dung.
- Burning of a candle.
What are the differences between reversible changes and irreversible changes?
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.
View full solution →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.
Can we reverse the following changes? If yes, suggest the name of the method:
- Water into water vapour.
- Water vapour into water.
- Ice into water.
- Curd into milk.
Paheli mixed flour and water and:
- Made a dough.
- Rolled the dough to make a chapati.
- Baked the chapati on a pan.
- Dried the chapati and ground it in a grinder to make powder. Identify the changes (i) to (iv) as the changes that can be reversed or that cannot be reversed.
Give examples to explain the difference between changes that can or cannot be reversed.
Give some examples from daily life where expansion of metal by heating is used. Explain.
Give one example in each case:
- Change which occurs on heating but can be reversed.
- Change which occurs on heating but cannot be reversed.
- Change which occurs on cooling but can be reversed.
- Change which occurs on mixing two substances, but can be reversed.
- Change which occurs on mixing two substances, but cannot be reversed.
Shilpa wanted to ind out which dye creates a permanent stain on clothes.
She poured one drop each of four different dyes on separate pieces of cloth.
Shilpa then washes each piece of cloth with a detergent.
The table below shows what happened after the clothes were washed.
$9.$ Which dye produced a permanent stain on the cloth?
$A.$ Dye$ 1$
$B.$ Dye $2$
$C.$ Dye $3$
$D.$ Dye $4$
$10.$ What must Shilpa keep the same for all the four clothes in her activity?
View full solution →She poured one drop each of four different dyes on separate pieces of cloth.
Shilpa then washes each piece of cloth with a detergent.
The table below shows what happened after the clothes were washed.
| Dye | Was the stain removed after washing? |
| Dye $1$ | yes |
| Dye $2$ | no |
| Dye $3$ | yes |
| Dye $4$ | yes |
$A.$ Dye$ 1$
$B.$ Dye $2$
$C.$ Dye $3$
$D.$ Dye $4$
$10.$ What must Shilpa keep the same for all the four clothes in her activity?
Leena had a glass container with butter cubes in it.
She could not open the metal cover as it was too tight.
Leena placed the container in a tumbler of hot water.
Leena took the container out of the hot water after $15$ minutes.
She was then able to remove the metal cover.
$5.$ How did hot water help in removing the metal cover?
$6.$ What is Leena likely to ind after taking the container out of hot water?
$A.$ Butter cubes have melted.
$B.$ Butter cubes have got larger.
$C.$ Butter cubes have got harder.
$D.$ Butter cubes have changed to a new substance
$7.$ Which of the following changes can be reversed?
Circle $‘Yes’$ or $‘No’$ to mark your response.
$8.$ Which condition must be true for a permanent change?
$A.$ Change in shape
$B.$ Change in volume
$C.$ Loss or gain of heat
$D.$ New substance is formed
View full solution →She could not open the metal cover as it was too tight.
Leena placed the container in a tumbler of hot water.
Leena took the container out of the hot water after $15$ minutes.
She was then able to remove the metal cover.
$5.$ How did hot water help in removing the metal cover?
$6.$ What is Leena likely to ind after taking the container out of hot water?
$A.$ Butter cubes have melted.
$B.$ Butter cubes have got larger.
$C.$ Butter cubes have got harder.
$D.$ Butter cubes have changed to a new substance
$7.$ Which of the following changes can be reversed?
Circle $‘Yes’$ or $‘No’$ to mark your response.
| Can this change be reversed? | $Yes$ or $No$ |
| Melting of wax | Yes/No |
| Shredding of paper | Yes/No |
| Bending of rubber pipe | Yes/No |
$A.$ Change in shape
$B.$ Change in volume
$C.$ Loss or gain of heat
$D.$ New substance is formed
Mary lit an incense stick.
She sensed a pleasant smell for as long as the stick was burning.
The incense stick burned up completely, leaving some ash behind.
$3.$ What can be concluded from Mary’s activity?
Circle $‘Yes’$ or $‘No’$ to mark your response.
$4.$ Which of these changes can be reversed?
$A.$ Boiling of egg
$B.$ Burning of wood
$D.$ Making curd from milk
$C.$ Melting of ice cream
View full solution →She sensed a pleasant smell for as long as the stick was burning.
The incense stick burned up completely, leaving some ash behind.
$3.$ What can be concluded from Mary’s activity?
Circle $‘Yes’$ or $‘No’$ to mark your response.
| Can this be concluded from the activity? | $Yes$ or $No$ |
| Incense sticks contain chemicals that produce smell when burnt | Yes/No |
| Burning of incense sticks produces light. | Yes/No |
| A new substance is formed by the burning of incense sticks. | Yes/No |
$A.$ Boiling of egg
$B.$ Burning of wood
$D.$ Making curd from milk
$C.$ Melting of ice cream
A chick hatches out from an egg by breaking the eggshell.
$2.$ Is the breaking of the eggshell a permanent change or a temporary change?
Explain your answer
View full solution →$2.$ Is the breaking of the eggshell a permanent change or a temporary change?
Explain your answer
The pictures show two types of change in objects.
Which statement about the two changes is true?
Circle $'Yes'$ or $'No'$ for the correct response.
View full solution →Which statement about the two changes is true?
Circle $'Yes'$ or $'No'$ for the correct response.
| $Yes$ or $No$ | |
| Change $1$ can be reversed. | $Yes/No$ |
| A new substance is formed in change $2.$ | $Yes/No$ |
| Change $1$ requires cooling but change $2$ requires heating. | $Yes/No$ |
Give some examples of physical and chemical changes.
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.
Classify the following changes in as many ways as you can:
- Breaking of a brick with a hammer.
- Beating of heart.
- Germination of a seed.
- Burning of an incense-stick (agarbatti).
- Occurrence of solar eclipse.
Paheli 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?
What are reversible and irreversible changes?
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