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Question
Describe an activity to demonstrate that warm air is lighter than cool air
Solution
(i) Take two same sizes of empty paper bags.
(ii) On the two ends of a wooden stick hang both of the bags in an upturned position.
(iii) In the centre of the stick tie a portion of the thread.
(iv) According to figure (A), hold the stick by the thread in balance.
(v) According to figure (B), place the burning candle below one of the bags.
(vi) Now, you will observe an unbalanced stick. This represents that as the warm/temperate air rises up and it pushes the bag over the candle.
(vii) Now we can say that when air is heated, it expands and also occupies more space. So, we can conclude that warm air is lighter as compared to cool air.
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