NCERT Solutions Class 6th Science Chapter – 6 Changes Around Us Question & Answer

April 22, 2022

NCERT Solutions Class 6th Science Chapter – 6 Changes Around Us

Textbook	NCERT
Class	6^th
Subject	Science
Chapter	6^th
Chapter Name	Changes Around Us
Category	Class 6th Science
Medium	English
Source	Last Doubt

NCERT Solutions Class 6th Science Chapter – 6 Changes Around Us Question & Answer In this Chapter We Will read about Changes by applying pressure, Changes by mixing a substance with other, Chemical changes, Physical changes, Characteristics of chemical changes, Contraction, Irreversible Changes and Physical And Chemical Changes etc. and More much. you have provided easy notes which use in your study make progress in education.

NCERT Solutions Class 6th Science Chapter – 6 Changes Around Us

Chapter – 6

Changes Around Us

Question & Answer

NCERT Solutions Class 6th Science (Chapter – 6) Question No – 1

Q. 1. To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?
Answer – Yes, it can be reversed by unfolding the dress.

NCERT Solutions Class 6th Science (Chapter – 6) Question No – 2

Q. 2. You accidentally dropped your favourite toy and broke it. This is a change you did not want. Can this change be reversed?
Answer – No, this change (breaking of toy) cannot be reversed.

NCERT Solutions Class 6th Science (Chapter – 6) Question No – 3

Q. 3. Some changes are listed in the following table. For each change, write in the blank column, whether the change can be reversed or not.

S. No.	Change	Can be reversed (Yes/No)
1	The sawing of a piece of wood
2	The melting of ice candy
3	Dissolving sugar in water
4	The cooking of food
5	The ripening of a mango
6	Souring of milk

Answer –

S. No.	Change	Can be reversed (Yes/No)
1	The sawing of a piece of wood	No
2	The melting of ice candy	Yes
3	Dissolving sugar in water	Yes
4	The cooking of food	No
5	The ripening of a mango	No
6	Souring of milk	No

NCERT Solutions Class 6th Science (Chapter – 6) Question No – 4

Q. 4. A drawing sheet changes when you draw a picture on it. Can you reverse this change?
Answer – No, we cannot get a fresh drawing sheet once a picture is drawn on it with paint oil or water. However, we can reverse the change, if a soft pencil is used to draw the picture.

NCERT Solutions Class 6th Science (Chapter – 6) Question No – 5

Q. 5. Give examples to explain the difference between changes that can or cannot be reversed.
Answer – Examples of reversible and irreversible changes

Reversible changes	Irreversible changes
1. Glowing of electric bulb. (It glows when switched on and becomes dark when switched off.)2. Distillation of liquid: 3. Sublimation 4. Collapsing of mimosa (touch me not) leaves on touching and opening up on removing the finger.	1. Burning of paper or wood. (It gives smoke and ash, which cannot form paper or wood again).2. Rusting of iron. (Rust cannot be changed into iron again.)3. Making of curd from milk.4. Growth of plants and animals.

NCERT Solutions Class 6th Science (Chapter – 6) Question No – 6

Q. 6. 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 immobilised. Can the change in POP be reversed?
Answer – No, the change in POP cannot be reversed since it is a chemical change.

NCERT Solutions Class 6th Science (Chapter – 6) Question No – 7

Q. 7. 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?
Answer – No, these are irreversible chemical changes.

EXTRA QUESTIONS

Q. 1. Give two examples of slow changes.
Answer –
(a) Growing of plants
(b) Ripening of fruits.

Q. 2. Give two examples of fast changes.
Answer –
(a) Blowing of balloon
(b) Rolling out roti from dough ball.

Q. 3. Give two examples of reversible changes.
Answer –
(a) Drying of wet clothes
(b) Heating of milk.

Q. 4. Give two examples of irreversible changes.
Answer –
(a) Milk to cheese
(b) Cooking of food.

Q. 5. Can you say deforestation is an irreversible or reversible change?
Answer – It is an irreversible change.

Q. 6. Does the size of the paper change after making an aeroplane by folding it or by cutting it?
Answer – Yes.

Q. 7. Can you change the shape of a eraser after erasing?
Answer – Yes.

Q. 8. Why does a blacksmith heat the metal rim to fix it on a cart wheel?
Answer – A blacksmith heats the metal rim to fix it onto a cart wheel because a metal rim is made slightly smaller. On heating, the rim expands and fits onto the wheel. Then on cooling, the rim contracts and fits tightly onto the wheel.

Q. 9. What are slow and fast changes? Give examples.
Answer – 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. Example –
(a) Rusting of iron, formation of day and night, 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. 10. Classify the following into slow and fast changes:

(i) Spinning of top
Answer – Fast change

(ii) Formation of day and night
Answer – Slow change

(iii) Formation of curd from milk
Answer – Slow change

(iv) Change of season
Answer – Slow change

(v) Making curd from milk by adding lemon juice.
Answer – Fast change

Q. 11. Classify the following as slow or fast change:

(i) Bearing of heart
Answer – Fast

(ii) Change of seasons
Answer – Slow

(iii) Burning of paper
Answer – Fast

(iv) Weathering of rocks
Answer – Slow

(v) Melting of wax
Answer – Fast

(vi) Cooking of food
Answer – Slow

(vii) Burning of wax
Answer – Fast

(viii) Melting of ice cream
Answer – Fast

(ix) Curding of milk
Answer – Slow

(x) Formation of day and night
Answer – Slow

Q. 12. Write some changes happening in our body.
Answer –
(a) Our nails grow
(b) Our hair grows
(c) We grow taller
(d) Our weight increases.

SHORT – QUESTIONS ANSWER

Q. 1. What is a physical change? Explain with example.
Answer – 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. Example: Boiling and freezing of water.

Q. 2. What is a chemical change? Explain with example.
Answer – The changes in which new substance with new chemical properties are formed are called chemical changes. Example – Reaction between washing soda and lemon juice in which C02 and other substances are formed.

Q. 3. What happens when sugar is heated?
Answer – When sugar is heated continuously then a black powdery substance is formed. This is a chemical change.

LONG – QUESTIONS ANSWER

Q. 1. Explain how a metal rim slightly smaller than a wooden wheel can be fixed on it.
Answer – The metal rim is always made slightly smaller than the wooden wheel. The metal rim is heated. On heating, the rim expands and fit onto the wheel. Cold water is then poured over the rim. Due to cooling the metal rim contracts and fits tightly onto the wheel.

Q. 2. How does curd being set? Is this change reversible?
Answer – A small quantity of curd is added to warm milk. The milk is stirred and is set aside undisturbed for a few hours at a warm place. In a few hours, the milk changes into curd. Curd formed from milk cannot be changed into milk again. So, this an irreversible (cannot be reversed) change.

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