Hot air balloons are devices of various sizes generally used for flight travel or entertainment purposes. They may be crafted in many shapes, but most possess similar features. In order to make a hot air balloon, an individual must usually have a fabric bag, a basket, and an open flame source. The latter object pumps hot air into the bag and makes it float. Licensing may be required for construction of commercial hot air balloons, while model hot air balloons can be crafted from common household items like candles and paper bags.
These objects were first crafted in the late 18th century in France. While early versions required wind propulsion and more modern versions can be moved with other sources of power, the basic makeup of the balloon has remained. Each variety must have a container for the hot air called the envelope. A smaller basket, or gondola, is used for carrying weight such as human passengers. Of course, the primary component to make a hot air balloon is the heat source: an open flame.
An individual who wishes to make a hot air balloon on a large scale will need these basic components. Envelopes are typically fashioned from fabric gas bags made of synthetic substances like nylon or polyester. This material must be cut into individual panels before the panels are joined together through sewing. Further, protective coatings may be applied to the fabric’s surface. The passenger-carrying component is attached to the balloon with a high-strength substance known as structural load tape.
In order to make a hot air balloon float, an opening — called a throat or a mouth — must be left at the bottom of the balloon shape for the hot air’s entrance. In addition, a burner must be affixed to the opening above the basket. This burner creates a flame that is usually sustained via a liquid gas called propane. While this flame is the main air source, commercial hot air balloons often must be at least partially inflated by some cold air beforehand. Piloting and navigating can be achieved with the addition of vents that release certain amounts of hot air from the envelope.
The invention of hot air balloons was successful due to basic scientific reasoning. Research and experimentation reveals that cold air is heavier than warmer air. When a flame lights the area underneath the balloon, or envelope, it gathers and becomes very hot because the air is trapped. The air surrounding the balloon is colder and, therefore, has more weight and density. This discrepancy allows the air contained within the balloon to rise and float along the cooler air source.
As a learning experiment, individuals may also make a hot air balloon on a small scale. This process would involve simulating the different components of an actual hot air balloon to make a model. For example, the hot air heating property and gondola could be recreated via a candle and some aluminum foil. If an individual gets two separate rolls of aluminum foil and then tapes the candle in the center of these adjoined structures, this will work as a stand-in for the structures. A paper bag can then be placed over the device to serve as the balloon, so that when the candle is lit, the bag will rise.