Understanding Warm and Cold Air

The video explains that warm air is lighter than cold air through a simple experiment. Two plastic bags are balanced on a stick, and a candle is placed under one bag. When the candle is lit, the warm air rises, causing the bag above it to lift. This demonstrates that warm air expands, occupies more space, and becomes lighter than cold air.

What is the initial setup for the experiment to demonstrate the properties of warm air?

• Two candles are placed below two plastic bags.

• A single plastic bag is placed on a table with a candle beside it.

• A plastic bag is filled with water and placed over a candle.

• Two plastic bags are hung on a stick with a candle below one.

What happens to the plastic bags when the candle is lit?

• The plastic bags remain balanced.

• Both plastic bags fall to the ground.

• The plastic bag above the candle rises.

• The plastic bag away from the candle rises.

Why does the plastic bag above the candle rise?

• The air inside the bag becomes heavier.

• The air inside the bag becomes colder.

• The warm air rises, pushing the bag upwards.

• The candle melts the plastic bag.

What happens to air when it is heated?

• It remains the same.

• It expands and becomes lighter.

• It turns into a liquid.

• It contracts and becomes denser.

How does the expansion of air affect its weight?

• It becomes heavier.

• It becomes lighter.

• It remains unchanged.

• It becomes solid.