Da Shuhua: the Chinese art of spraying melted iron to create fireworks

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2 years ago Robin

Known as “the poor man’s fireworks”, Dashuhua (打树花 ) is a 500-year-old pyrotechnic ritual used in Nuanquan, a small town in northwestern China’s Hebei province.
It has been classified as one of China’s significant examples of intangible cultural heritage by UNESCO (United Nations Educational, Scientific and Cultural Organization ) and the provincial intangible cultural heritage in Hebei. It marks the start of the Dragon Boat Festival, a traditional Chinese holiday which occurs on the fifth day of the fifth month of the Chinese calendar, and also used to celebrate the Lunar New Year.

And It is one of the world’s most mesmerizing (but dangerous) fireworks displays.
Although fireworks have been a part of Chinese celebrations since around the year 800 A.D., they haven’t always been as widely available and affordable as they are today.
So about half of a millennia ago, local blacksmiths came up with a viable alternative that was cheaper, but just as impressive as conventional pyrotechnic games: in short, throwing molten iron at cold walls to produce a waterfall of bright sparks that are, at the same time, amazing and dangerous.

As you can imagine, having bits of molten iron raining from above isn’t the most recommended thing in the world, and those brave enough to carry out the annual celebration boast the burn marks to prove it.
Even though blacksmiths usually wear the customary large straw hat and cover themselves with sheepskins, accidents can happen, so performers need to be extra careful.
The wooden spoon used by blacksmiths to scoop out molten iron cannot go very deep into the molten metal, otherwise, the temperature difference between the cold spoon and heated iron can cause even an explosion.
And the iron is heated up to 1,600 degrees Celsius (2,910 degrees Fahrenheit), so you definitely don’t want it anywhere near your skin!
To be more precise, the splash of heated liquid iron is basically an energy transformation process: when the blacksmith throws out the iron from the furnace, kinetic energy is supplied to the bulk of the liquid iron that transforms to potential energy at an elevation up the wall, and the residual kinetic energy is responsible for a splashing impact. The explosion of molten iron is essentially an oxidation reaction of finely divided iron droplets combined with scattering upon collision with the wall. In addition, carbon impurities in the iron will react with oxygen to produce carbon dioxide and the impact will expose carbon in the molten iron to oxygen to produce sparks.

Either way, Dashuhua is unique to the town of Nuanquan, whose inhabitants still today save up scrap metal to donate to blacksmiths for the annual celebration.
In turn, blacksmiths have incorporated other metals, such as copper and aluminum, into their performances in order to create green and white sparks in addition to the traditional orange ones.
Even though there are few young blacksmiths left in Nuanquan to take up the mantle from the last generation, for the time being, Dashuhua is safe at this moment, and It is more popular than ever before, with people come from far and wide to see the falling molten metal with their own eyes.