Question 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 this change of folding the dress can be reversed by unfolding it.

Question 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 of breaking the toy cannot be reversed.

Question 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.

Answer:-

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

Answer:-  This change can be reversed if pen is used to draw the picture. But in case of a pen or any type of colours are used to draw the picture, change cannot be reversed.

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

Answer:- Changes that can be reversed

1. i) Opening and closing the copy.
2. ii) Filling bottle with water.

Changes that cannot be reversed

1. i) making of curd.
2. ii) Ripening of fruit.

Question 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:-  Since it is a chemical change so, No, the change cannot be reversed.

Question 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:-  Since it is a irreversible chemical change so, No, the change cannot be reversed