July 14, 2011
Technically, hot-air balloons are simplest transportation and technological discovery that human civilization created. One of the least expensive and easiest air power transportation uses a full balloon where the air warming by gas burner. Large balloons filled with hot air or buoyant gas (often hydrogen or helium) have been used as flying machines since the 18th century. Hot air balloon flies when the gas inside the balloon expands the extra gas is pushed out the bottom of the balloon, meaning that there are fewer atoms inside the balloon, meaning that the air in the balloon is lighter than the air outside the balloon. On this picture a pilot prepares a hot air balloon for flight.