Class 6 Science Chapter 6 Exercises

 

Chapter 6 : Changes Around Us

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

Ans: Yes, it can be reversed by unfolding the dress.

 

2. You accidentally dropped your favourite toy and broke it. This is a change you did not want. Can this change be reversed?

Ans: No, this change (breaking of toy) cannot be reversed.

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

 

Ans:

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

 

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

Ans: No, we cannot reverse this because we will not get fresh drawing sheet once a picture is drawn on it by pen, paint or marker etc. However it can be reverse if we draw a picture by a pencil.

 

5. Give examples to explain the difference between changes that can or cannot be reversed.

Ans: Examples of reversible and irreversible changes

Reversible changes:

a)    Melting of Ice

b)   Boiling of water

c)    Glowing of electric bulb

d)   Warming of milk

e)    Filling of water bottle etc.

Irreversible changes:

a)    Burning of paper

b)   Curdling of milk

c)    Growth of plants and animals

d)   Ripening of fruits

e)    Rusting of iron etc.

 

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?

Ans: No, the change in POP cannot be reversed because when POP gets hardened, it can’t be soften/powdered. Hardening of POP is a chemical change which cannot be reversed.

 

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?

Ans. No, the change is not reversible because it is also a kind of chemical change.

Solution of Exercises of Chapter 1; Food: Where does it come from.

Solution of Exercises of Chapter 2; Components of Food.

Solution of Exercises of Chapter 3; Fibre to Fabric.

Solution of Exercises of Chapter 4; Sorting Materials into Groups.

Solution of Exercises of Chapter 5; Separation of Substances.

Solution of Exercises of Chapter 6; Changes around us.

Solution of Exercises of Chapter 7; Getting to Know Plants.

Solution of Exercises of Chapter 8; Body Movements.