How/ Why Do Hot Air Ballons Work?

The hot air balloon is first filled with hot air by a burner. This cause it to float.

The pilot can then control the altitude of the balloon by adjusting the amount of heat applied by the burner. The more heat he applies, the higher the balloon goes and the less heat applied, the lower the balloon.

When landing the pilot will slowly release hot air from the balloon letting it land.

The balloon floats since the air inside of the balloon is less dense than the surrounding air. This is because the air inside the balloon is heated up causing molecules to spread out and move faster creating less dense air.

The balloons altitude can change from the amount of heat applied because heat affects density. If more heat is added, molecules will spread apart creating a lower density. At this point the ballon will weigh less allowing it to travel farther into the sky. The less heat added the closer the particles will get to each other. Since the particles are closer the density will become greater making the hot air balloons altitude decrease.

The hot air balloon lands from the release of hot air because the density is becoming greater. The air particles inside of the balloon are becoming closer together and moving less letting the balloon fall to the ground.