Why do hot air balloons float?

The video explains how hot air balloons work. Initially, the balloon is a flat bag on the ground. The pilot uses burners to heat the air inside, causing the molecules to move more and the air to expand, making it less dense than the surrounding cold air. This density difference allows the balloon to rise. To land, the pilot lets the air cool, making it denser and causing the balloon to descend.

What is the initial appearance of a hot air balloon before it takes off?

• A small, compact ball

• A flat bag on the ground

• A fully inflated sphere

• A floating object in the air

What role do the burners play in the operation of a hot air balloon?

• They inflate the balloon with helium

• They deflate the balloon

• They cool the air inside the balloon

• They heat the air inside the balloon

Why does hot air inside the balloon cause it to rise?

• Hot air is more colorful than cold air

• Hot air is heavier than cold air

• Hot air is less dense than cold air

• Hot air is more humid than cold air

What happens to the molecules inside the balloon when the air is heated?

• They slow down and take up less space

• They move around more and the air expands

• They disappear completely

• They become larger in size

How does a pilot make the balloon descend?

• By adding more air to the balloon

• By cooling the air inside the balloon

• By heating the air inside the balloon

• By releasing helium from the balloon