39. NCERT Exemplar XVII

 

1. Take two empty steel cupspaper cupsmetal cups of the same size.

2. Hang it in the inverted positionupright positionslanting position on the two ends of a metal or wooden stick.

3. Tie a piece of plasticthreadmetal in the middle of the stick.

4. Hold the stick as in a basketweightbalance.

5. Put a waterburning candlecandle below one of the cups.

Inference:

 

The paper cup is pushed upwardspulled downwardspushed to the sides because the warm air being lighter riseswarmer riseslighter stays and fills the space inside it. Therefore, one side of the stick becomes heavier, moves upwardslighter, moves upwards and thus, the balance is disturbed. From this experiment, it is evident that warm air does not risecold air riseswarm air rises.