NCERT Solutions for Class 6 Science Chapter 6 Question Answers of Changes Around Us updated for new academic session.

Class 6 Science Chapter 6 NCERT Solutions

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, by unfolding the dress this change can be reversed.

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, it cannot be reversed, so it is an irreversible change.

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.

ChangeCan be reversed (Yes/ No)
The sawing of a piece of wood
The melting of ice candy
Dissolving sugar in water
The cooking of food
The ripening of a mango
Souring of milk

Answer:

ChangeCan be reversed (Yes/ No)
The sawing of a piece of woodNo
The melting of ice candyYes
Dissolving sugar in waterYes
The cooking of foodNo
The ripening of a mangoNo
Souring of milkNo
Question 4. A drawing sheet changes when you draw a picture on it. Can you reverse this change?

Answer:
It is all depends on situations:

    • By erasing the drawing we can undo the change. For example, if we draw with the help of pencil, we can erase the drawing by using an eraser. Then, it is a reversible change.
    • If we draw using a pen, we cannot erase the drawing. Then this change cannot be reversed, so it is irreversible change.
Question 5. Give examples to explain the difference between changes that can or cannot be reversed.

Answer:
Examples of Reversible Changes:
1. Melting of Ice into water. By freezing the water we can obtain ice again.
2. Folding a paper: By unfolding it, we can undo the change.
3. Hot milk to cold milk: By boiling milk, we can make it warm.
Example of Irreversible Changes:

    • Burning of candle.
    • Bursting of crackers.
    • Cutting of trees.
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:
When water is added to POP, it undergoes a chemical change. Its composition changes and is converted into another substance. Since it is a chemical change, so it 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:
Due to water, cement hardens and its composition changes. Since it is a chemical change which cannot be reversed.

Solutions App for Class 6