How Hot-Air Balloons Work

Hot-air balloons operate on the principle that hot air is lighter than cold air and thus will rise. To get the air inside a balloon hot enough to rise, it has to be heated. Propane ignites a flame when the pilot pulls a lever to heat up the air. The air causes the balloon to float up because hot air rises and the balloon captures the air. The pilot can’t keep the switch held in, though, or it could set the balloon on fire. He can only hold it in for about five seconds. There are weight bags on the side of the balloon’s basket to keep its balance.

Hot air balloons don’t fly when it is raining because the balloon’s heat causes the water to boil atop the balloon, and the balloon would start to drop. Balloons for the Hilbert School District will be coated with Rain-X, a special chemical that causes rain water to sheet off the surface, therefore allowing the balloons to run during rainy weather.