How Hot Air Balloons Work

Hot air balloons are one of the simplest and most beautiful ways to fly. They work on a simple principle: hot air rises. A burner heats the air inside the balloon. The hot air is lighter than the cooler air outside. This makes the balloon float upward, carrying the basket and passengers with it.

Why Hot Air Rises

When air is heated, its molecules spread apart and move faster. This makes the air less dense, meaning it is lighter for its volume. The cooler, heavier air around the balloon pushes under the lighter hot air and forces it upward. This is the same reason smoke rises from a campfire.

Controlling the Balloon

The pilot controls the balloon's altitude using a propane burner. Firing the burner heats the air and the balloon rises. Opening a vent at the top lets some hot air escape, and the balloon descends. Pilots cannot steer left or right directly. Instead, they go up or down to find wind blowing in the direction they want to go.

Fun Facts

• The first hot air balloon flight was in 1783 in France, carrying a sheep, a duck, and a rooster.
• A hot air balloon envelope holds about 77,000 cubic feet of air, enough to fill a small house.
• The record altitude for a hot air balloon is over 68,000 feet, higher than most jet airplanes fly.

Did You Know?

The first passengers on a hot air balloon were not people. In 1783, the Montgolfier brothers sent a sheep, a duck, and a rooster up in a balloon to test if living creatures could survive at altitude. All three animals landed safely!