A hot air balloon is an air balloon whose upper half is an atmospheric ball and the lower half is a hanging basket.

The inside of the balloon heats the air, which has a lower density than the cold air outside and acts as buoyancy to move the whole thing. The basket can carry passengers and a heat source (mostly an open flame). Modern sports balloons are usually made of nylon fabric.

Hot air balloons can be used for aviation sports, photography, tourism, and so on. The first manned hot air balloon was made by the Montgolfier brothers and launched on 21 November 1783 by Jean-Francois Pilatre de Rozier and Francois Laurent d'Arlandes in Paris, France.

The first hot air balloon to fly in the Americas was launched by French airline Jean Pierre Blanchard from Philadelphia on January 9, 1793.

Hot air balloons were invented in Europe in the 18th century by the Montgolfier brothers, a French paper merchant. Inspired by the rising of scraps of paper in a furnace, they used paper bags to concentrate hot air, allowing the bags to rise with the current.

On June 4, 1783, the Montgolfier brothers gave a public performance at the Place de l 'Annone in Lyon, when a mock balloon with a circumference of 110 feet was lifted and traveled 1.5 miles.

On September 19 of the same year, in front of the Palace of Versailles in Paris, the Montgeffe brothers for the king, Queen, court ministers, and 130,000 Parisians in a hot air balloon performance. On the afternoon of November 21 of the same year, the Montgeffe brothers carried out the world's first manned flight of hot air balloons in the Paris Mouetteau.

The flight lasted 25 minutes and flew over half of Paris before landing near the Piazza Italia.

This flight preceded the flight of the Wright Brothers by a full 120 years. In terms of inflating balloons, the French brother Robert was the first to fly into the sky in a balloon filled with hydrogen gas.

A hot air balloon is a balloon that uses hot air as a rising gas. At the bottom of the airbag is a large opening for cold air heating and a hanging basket. The density of air decreases after heating.

When the temperature reaches 100℃, the density is about 0.95kg/m3, which is 1/1.3 of air. So the liftoff is not very high. Modern hot air balloons are equipped with simple flight instruments, fuel tanks, and blowtorches in the hanging basket.

Hot air balloons appeared the earliest, now flying by hot air balloons has become a favorite aviation sport. In addition, hot air balloons are often used for aerial photography and air tourism.

The International Aviation Federation has ranked hot air balloons as the safest aircraft. Based on the data alone, the safety factor of hot air balloons is also quite high. Hot air ballooning is gaining popularity as a sport, with a record 34,668 meters high.

The basic principle of a hot air balloon's ascent is that heat expands and cold contracts. As the air expands with heat, it becomes lighter and rises upward. Because air is a mass matter, the same volume of air, different temperatures, density, and mass are different.

The heated air inside the balloon becomes less dense and lighter than the same volume of cold air outside the balloon, so the balloon generates buoyancy and lifts off. For aircraft, we call this buoyancy force lift.

When the air in the balloon is heated by the burner, the air in the balloon expands, the density becomes smaller, and the excess air is discharged from the bottom of the balloon after expansion.

Then the balloon can go up. A hot air balloon flight is based on hot air lighter than cold air to generate lift and aerostatics principles. The gas temperature in the balloon is adjusted by the time and frequency interval of ignition and extinguishing of the burner.

To control the rise and fall of the hot air balloon, using different levels of wind direction to control and adjust the direction of travel, the speed of the hot air balloon flight is roughly the same as the wind speed.

A hot air balloon consists of a balloon, basket, and heating device in three parts, the ball is made of reinforced nylon, and despite its lightweight, but extremely strong, the balloon is not breathable.

In recent decades, hot air balloons is mainly used for aviation sports and sightseeing, and gradually developed into fashionable and healthy outdoor leisure sports.

So far, there are about 20,000 hot air balloons around the world. In developed countries such as Europe and America, there are almost every day hot air balloon competitions or activities.