Describe an activity to demonstrate that warm air is lighter than cool air.

AcademicPhysicsNCERTClass 7

Step 1. Let\'s take two paper bags of the same size.

Step 2. Hang both the paper bags to both ends of a stick or rod as shown in figure $(A)$.

Step 3. Tie a piece of thread or rope to the middle of the stick.

Step 4. Hold the stick with one hand to balance it.

Step 5. Place a candle below one of the two bags.

It is observed that the bag below which the candle is placed is used up as shown in figure $(B)$. This is because the air become lighter and expands. This activity proves that warm air is lighter than cool air.

Updated on 10-Oct-2022 13:29:50