As the day gets closer, the anticipation grows for the staff of Macy’s and their World famous 4th July fireworks display.
For days there is a huge operation concerning engineers, TV, Police, City and Government Officials, vendors and volunteers totalling around 5000 individuals to plan and co-ordinate to lessen any issues which may arise.
The display will be the vision of Gary Souza (of Sousa fireworks) and his firing team only have the one chance to get in right as there can be no rehearsals of this event as is the name of the game in fireworks.
This year’s display is destined to be one of the biggest and best ever but no matter how technical the launch controls etc, the story of fireworks begins half a works away in Liuyang, China. They are so proud of the tradition, there is even a statue to fireworks in the city itself reflecting the history of pyrotechnics and they still continue to produce many millions of tons of fireworks every year to export around the globe.
One of the biggest manufacturers of fireworks in China is Black Cat. For all their modern packaging and the graphics used, fireworks are produced using the same techniques as having been used for over 2000 years.
Of course, the blending of chemicals is very dangerous and this is why much of the production area remains in the mountainous regions of Hunan Province. The old adage for fireworks is mixed by day, tested by night.
Many years ago, the original firecrackers were made from bamboo filled with ‘black powder’ which gave the popping effect. However, it was discovered that if the powder was packed into a tight space and then loaded into a tube, ‘Kaboom’!!! This is now described as the bursting charge. Then, they found that if a hole (also known as a choke) was put into the firecracker at the base this pushed the force downwards making the firework fly. This is known as the lift charge.
How do they create the fancy effects like cascades, clusters etc? These are created from rice husks coated in glue and gun-powder and called pearls or stars. These are then packed into spheres and then they add whatever salts are required to create the colour effects:
• Strontium – red
• Barium – green
• Sparkle – flakes of aluminium
The resulting firework, whether a shell or a rocket, will contain a time delay fuse to ensure that the desired effect is created in the air rather than on the ground when it is launched.
All fireworks, however big and complex, are based on this chain reaction and the effects just change with the amount of rice used or shell size.
Darkness falls and anticipation rises in New York as the team are set up and ready to go setting the sky alight with multicoloured and multi-effect explosions across the Manhattan skyline. They use an average of 1000 shells a minute and 40,000 tons of high explosives is launched into the sky which will be nothing short of awesome.
Technology of fireworks is 2000 years old but still continues to offer some staggering effects.