The Class is an important year in a student's life and this subject requires dedication, hard work, and practice. It's a subject where you can score well if you are well-versed with the concepts, remember the important formulas and solving methods, and have done an ample amount of practice. Worry not! Home Revise is here to make your journey even easier. It's essential for students to have the right study material and notes to prepare for their board examinations, and through Home Revise, you can cover all the fundamental topics in the subject and the complete syllabus.
Exercise Questions
1. To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?
Solution:
Yes, the process can be reversed.
2. You accidentally dropped your favourite toy and broke it. This is a change you did not want. Can this change be reversed?
Solution:
No, this change 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.
| Sl. 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 |
Solution :
| Sl. 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?
Solution:
This change can be reversed if a pencil is used to draw the picture. If a pen, paint, or oil/water colours are used to draw the picture, change cannot be reversed.
5. Give examples to explain the difference between changes that can or cannot be reversed.
Solution:
Changes that can be reversed are as given below:
i) Opening and closing the door
ii) Filling glass with water
Changes that cannot be reversed are as given below:
i) Conversion of milk into curd
ii) Ripening of fruit
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?
Solution:
No, the change 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?
Solution: No, the change cannot be reversed
