Yes, this change can be reversed. We usually shorten the length of our dress by folding it. It can be reversed by unfolding the length of the dress. So this change is an example of reversible changes.
No, this changes cannot be reversed. If a toy is broken accidently than actually fixing it. After fixing, it will not be in the same condition as it was before. So this change cannot be reversed.
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 |
1. No
It cannot be reversed because after sawing piece of wood would be in the same condition.
2. Yes
This can be reversed by freezing the ice candy again.
3. Yes
This can be reversed by vaporization.
4. No
This cannot be reversed because we cannot change the cooked food again into raw materials.
5. No
This cannot be reversed because ripening of mango is a natural process.
6. No
This cannot be reversed because souring of milk is due to bacteria which is an irreversible change.
No, we cannot reverse this change if the picture drawn on a drawing sheet with colours. But we can reverse it, if the picture is drawn by a pencil, then by erasing it we can reverse the change.
The changes which can be reversed called as reversible changes. For example:
The changes which cannot be reversed called as irreversible changes. For example:
No, the change of POP cannot be reversed because when a thick coating of POP is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured immobilized. After drying it, POP undergoes a chemical reaction due to it, cannot be reversed.
No, this change cannot be reversed because cement makes a hard product after mixing with water or when it comes in contact of moisture. This change cannot be reversed because it is due to chemical reaction.