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Question
A drawing sheet changes when you draw a picture on it. Can you reverse this change?
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Solution
If we draw a picture on a drawing sheet with a pencil, we can get back the original drawing sheet by erasing the drawing with an eraser. In this case, the change can be reversed.
However, if we draw with a pen, then the original drawing sheet cannot be obtained back because we cannot erase ink. Hence, in this case, the change cannot be reversed.
RELATED QUESTIONS
Very Short Answer Type Question:
Can you say deforestation is an irreversible or reversible change?
Very Short Answer Type Question:
Some common changes are given in the below Table. Which of these changes do you think can be reversed?
| Change | Can be reversed |
| (i) Raw egg to boiled egg | Yes/No |
| (ii) Batter to idli | |
| (iii) Wet clothes to dirty clothes | |
| (iv) Woollen yarn to knitted sweater | |
| (v) Grain to its flour | |
| (vi) Cold milk to hot milk | |
| (vii) straight string to a cold string | |
| (viii) Bud to flower | |
| (ix) Milk to paneer | |
| (x) Cow dung to biogas | |
| (xi) stretched rubber band to its normal size | |
| (xii) Melting of ice-cream |
Match the following.
| Bud to flower | Dr. A.P.J. Abdul Kalam |
| Reversible change | Recyclable waste |
| India 2020 | Organic waste |
| Paper | Melting of ice |
| Vegetables | Irreversible change |
Analogy
Dissolution of glucose : reversible change :: Digestion of food: ___________ change
Choose the odd one out. Give reason for your choice.
Inflating a balloon, popping a balloon, fading of wall paint, burning of kerosene
Pick the change that can be reversed from the following.
Can we reverse the following change? If yes, suggest the name of the method.
Water into water vapour
Boojho’s sister broke a white dove, a symbol of peace, made of Plaster of Paris (POP). Boojho tried to reconstruct the toy by making a powder of the broken pieces and then making a paste by mixing water. Will he be successful in his effort? Justify your answer.
Give one example of change which occurs on heating but can be reversed.
Choose the odd one out. Give reason for your choice.
