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, this can be reversed.

Q2. You accidently dropped your favorite toy and broke it. This is a change you did
not want. Can this change be reversed?

ANS -: No, this change cannot be reversed.

Q3. 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
1.                                      The sawing of a piece of wood.                     Yes/No
2.                                      The melting of ice candy
3.                                      Dissolving sugar in water
4.                                      The cooking of food
5.                                      The ripening of 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 cand                                             Yes
3.                                                Dissolving sugar in water                                        Yes
4.                                                The cooking of food                                                  No
5.                                                The ripening of mango                                            No
6.                                                Souring of milk                                                         No

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

ANS -: If the picture is drawn with a pencil, then it can be erased; hence change can be
reversed. But if the picture is drawn with colours, the change cannot be reversed.

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

ANS -: Some changes can be reversed like:
(i) Filing glass with water
(ii) Opening/ closing door
Other changes cannot be reversed, like:
(i) Curdling of milk
(ii) Ripening of fruit.

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.

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

ANS -: No, the changes which have occurred in the cement cannot be reversed.