NCERT Solutions for Class 6th Science

Chapter 6 - CHANGES AROUND US

(Complete Downloadable Chapter Solution PDF file is at the bottom of the page)

 

Q.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, one can unfold the dress to make it long. So this change can be reversed.

 

Q.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 can not be reversed. It is an irreversible change.

 

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

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

 

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

 

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

 

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?

 

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?

Ans     No. Cement after reacting with water gets hardened and this hardened substance can not be changed to              original state. Hence this change cannot be reversed.