Fireworks history begins in China around 200 BC, when someone tossed green bamboo into a fire. Pockets in the bamboo trapped superheated air, leading to crackles, pops, and an eventual explosion. The Chinese soon came to believe that the noise could ward off evil spirits.
In the 9th century AD, Chinese alchemists developed the precursor to black powder, huo yao (the fire drug), and the first modern fireworks were born. By the 1400s, Chinese fireworks had become quite popular in Italy, leading Renaissance artisans to develop the first artistic fireworks.
Although today’s fireworks are more sophisticated, their basic creation has not changed. Here is how fireworks are made.
Shells and Stars
The shell, or the outside of the firework, is no long made of green bamboo. Instead, modern shells are rather boring-looking cylinders crafted from heavy paper and cardboard. Inside the shell, the stars are the pieces that determine the effect the firework will create. Stars come in many variations, from tightly pressed pieces of clay that look like batteries to big, doughy balls.
The size, shape, and arrangement of the stars work together to determine the pattern and effect. Larger stars have more to burn, so they travel further into the sky and stay lit for longer. Pressed stars have more mass, creating the broad strokes and frayed edges of a weeping willow effect. The stars will explode in whatever pattern they are arranged in, such as a smiley face or a heart shape.
Chemical Components
Fireworks are based on a tight sequence of chemical reactions. Therefore, each shell must contain a fuel source along with just the right blend of oxidizers and reducing agents. Each manufacturer’s recipes are carefully protected trade secrets, but the basic process remains the same.
Lighting a firework detonates a lift charge that propels the firework into the air, lights a time-delayed fuse, and triggers a rapid series of chemical reactions. When the firework reaches the top of its arc, it explodes, releasing the stars in a shower of effects.
Color Considerations
To create colors, the stars contain metals or metal salts. As the shell heats up, the energy excites the metal or metal salt’s electrons. When the shell explodes, the excess energy is emitted as light. Different metals and metal salts have different sized gaps between their ground state and their excited state. This causes them to emit light at different wavelengths, which our eyes see as different colors.
Each manufacturer uses its own proprietary formulation. In general, though, white or silver fireworks contain aluminum, magnesium, titanium, or beryllium. Pale reds are often lithium carbonate, while intense reds may be strontium carbonate. Yellow fireworks generally contain sodium compounds, and gold fireworks may have charcoal, lampblack, or iron. Calcium chloride creates bright orange fireworks, while copper chloride may be responsible for vibrant blues. Purple fireworks are often a blend of copper chloride and strontium carbonate.
Special Effects
Many modern fireworks create a variety of effects from a single shell. While the trade secrets remain a mystery, science can help us understand the techniques. Quite elaborate patterns can be created simply through hand-arrangement of the stars inside the shell.
In addition, the shell itself may be a multi-break. When the big external shell bursts open, it launches several smaller shells into the sky. These may explode at slightly different times, creating layered effects, or may explode at virtually the same moment, as often happens during an ear-popping finale.
At Dynamite Fireworks, we don’t only sell top-quality, name-brand fireworks. We also provide the information you need to know to use them responsibly, legally, and safely. If you have any questions or concerns, give us a call at (219) 937-4090. We look forward to becoming your one-stop shop for all your fireworks needs!