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Meriam buluh (Jawi: مريام بولوه) or Kawayang Kanyon (bamboo cannon) is a type of home-made firecracker which is popular during the Hari Raya festive season in Malaysia, and during the New Year's day celebration in the Philippines. Like other fireworks, bamboo cannons are illegal as stated in Malaysian Explosive Act 1957; ironically, more Malay children turn to the more dangerous bamboo cannon as an alternative to commercial firecrackers which were made illegal by the government.
How it works
A typical bamboo cannon consists of a large bamboo tube section containing some water to which a little calcium carbide is added. The carbide reacts immediately with the water releasing acetylene gas. Acetylene has the widest range of explosive limit of any common chemical and also a very low ignition energy; a sharp retort is produced when a flame is introduced into the bamboo chamber. However, the low density of the acetylene/air mixture is such that the total combustion energy is quite low and weak containers such as bamboo or even glass rarely shatter. Adding too much carbide does not increase the energy of the explosion but instead weakens it. After the shot, fresh air is needed in the tube in order to have another explosion after more carbide is added.
The operating principle also works with other combustable fuels besides acetylene, but since most others have narrower explosive limits, the effect is not as reliable. Common examples are solvent-containing aerosol consumer products such as spray paint or hairspray.
Less-volatile fuels can also work, with skill, such as 200ml of hot kerosene, poured into a small hole near the breech of the cannon. A lighting stick is used to ignite the fumes and fire the cannon, then fresh air is blown into the small hole and the cannon fired again. The bamboo used for this is usually around 4 to 6 inches in diameter and 4 to 5 feet long.