Hot air rises.
The envelope traps a large bubble of hot air. If the air in the envelope is heated by a burner, the balloon will rise. The Balloonfest is an annual celebration that people all over the area come to see. It's exciting to see the balloon's float right over your home and hear the faint gush of air being blown into the balloons. The Civil War re-enactment taking place during the Fest is where people from the community camp out in an open field near U.S. 42 and pretend they are soldiers in the Civil War.