Sky lantern

A sky lantern (), also known as Kǒngmíng lantern (), or Chinese lantern, is a small hot air balloon made of paper, with an opening at the bottom where a small fire is suspended. Sky lanterns have been made for centuries in cultures around the world, to be launched for play or as part of long-established festivities. The name sky lantern is a translation of the Chinese name but they have also been referred to as sky candles or fire balloons. Several fires have been attributed to sky lanterns, with at least one 21st-century death caused. Sky lanterns have been made illegal in several countries such as Vietnam which has banned the production, sale, and release of sky lanterns throughout the country since 2009. Many areas of Asia do not permit sky lanterns because of widespread fire hazards as well as danger to livestock. The general design is a thin paper shell, which may be from about 30 cm to a couple of metres across, with an opening at the bottom. The opening is usually about 10 to 30 cm wide (even for the largest shells), and is surrounded by a stiff collar that serves to suspend the flame source and to keep it away from the walls. When lit, the flame heats the air inside the lantern, thus lowering its density and causing the lantern to rise into the air. The sky lantern is only airborne for as long as the flame stays alight, after which the lantern sinks back to the ground. In China, Taiwan and Thailand, sky lanterns are traditionally made from oiled rice paper on a bamboo frame. The source of hot air may be a small candle or fuel cell composed of a waxy flammable material. In Brazil and Mexico sky lanterns were traditionally made of several patches of thin translucent paper (locally called "silk paper"), in various bright colors, glued together to make a multicolored polyhedral shell. A design that was fairly common was two pyramids joined by the base (a bipyramid, such as the octahedron) sometimes with a cube or prism inserted in the middle.