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    Categories: Local News

The science of fweeeeeeeeBOOM!

HAPPY NEW YEAR – A shot of the 2011 New Year's Eve fireworks show at Mission Hill by Thunder F/X. Spectacular displays such as this rely on complex chemistry and physics.

Rob Kowalyshyn knows the best way to ring in the new year – with explosions.

He and the rest of the Thunder F/X Fireworks crew are spending today setting up about a bazillion pounds of kaboom on Mission Hill in preparation for the 11th annual Victory Life Church New Year’s fireworks show.

“That particular show should be somewhere in the neighbourhood of 9,700 shots,” says Kowalyshyn, including the titanium salute: a three-inch ball that produces a blinding white flash and the explosive force of half a stick of TNT upon detonation. He plans to set off about 30 of those during the finale.

He’ll also have chrysanthemums, spiders, planets and peonies in a universe of colours, all ready for launch come 8:30 p.m. this evening.

Some will crackle, others will whistle or rattle windows – and all rely on the science of chemistry.

“It’s quite an art form,” he says.

The colours

A St. Albert resident, Kowalyshyn has been in the fireworks business for about 24 years and has run every pyrotechnical display in the city for the last decade or so.

Fireworks have been around for centuries in places like China and rely on a combination of burning chemicals to produce their spectacular colours, he says.

Paul Kane chemistry teacher Michael Ng discusses fireworks in his talks on elemental properties.

Every element is made of atoms with electrons, and those electrons can only exist at specific energy levels, Ng explains.

Combustion occurs when you have different elements (typically metals with fireworks) react with oxygen after the addition of energy (a spark), Ng says. The electrons in the metals get pushed to a higher energy level, making them unstable, which makes them dump energy as either heat or light to get back to normal.

Those electrons spit out a specific amount of energy at a set wavelength whenever they change levels, with different level shifts producing different colours of light.

Firework manufacturers use this principle to get different colours. You get gold from carbon, blue from copper, green from barium, yellow from sodium and red from strontium. Ng lights several colourful fires in little bowls to demonstrate.

Fireworks use substances called oxidizers that release many oxygen atoms when burned to accelerate combustion, Ng continues. A gummy bear will produce only a weak flame when lit normally, for example, but the addition of a potassium chlorate oxidizer creates a roaring white-hot pillar of fire that fills the room with smoke.

How to make a star

New York’s Fireworks by Grucci is one of the few companies in North America that still makes its own fireworks. The family-owned business has been making fireworks since 1850 and in 2013 set the Guinness World Record for the world’s biggest fireworks display, launching some 479,651 shells in six minutes.

Most fireworks are still made by hand due to their complex designs, says Phil Grucci, president of Fireworks by Grucci.

“The workhorse of the fireworks display industry is the aerial shell,” he says, which is typically spherical. Most range from four to six inches (10 to 15 cm) in diameter, but there are some that get up to 24 inches.

Most shells are made in China, with some coming from Europe and Mexico, Grucci says, speaking in his Italian-American accent. Chinese shells tend to be spherical with flower-burst patterns, while European ones are usually cylindrical and make lots of whistles and serpent-patterns.

The process starts with rolled balls of pyrotechnical composition called (rather poetically) stars, Grucci says.

“These are made very similar to a jawbreaker,” he says, in that they often have different colour layers.

If you want the star to burn white, yellow and red, for example, you might start with strontium (red), layer on sodium (yellow) and finish with magnesium (white), as it will burn outside in.

Workers toss powdered chemicals into a spray of water to create the seeds of the stars. These seeds roll around in a mixer until they release the desired size – typically 0.6 to 6 cm wide.

The combination of elements and oxidizers used determines the colour produced. Copper and strontium make purple, for example, while copper with lots of oxidizer burns super hot to make powder blue instead of dark blue. Adding flakes of metals that burn super-bright (such as iron or magnesium) adds sparkles to the explosion.

Finished stars are dried in an oven-like chamber, Grucci continues. Dry them too fast, and the stars will crack and not change colours in the order you want.

Next, crews construct the outer casing of the firework from glue and wet crafting paper. The shells must be hard enough to withstand launch yet soft enough to eventually split open.

The casing has a black powder fuse on the outside connected to a black powder charge on the inside. (Some have computer chips for more precise control.) Workers surround the charge with stars, making sure that the charge is properly centred for even star dispersal.

“The stars need to be placed in the same pattern you expect to see in the sky,” Grucci says – if you want a smiley face, you place the stars in the shape of a smiley face.

Some fireworks contain sub-munitions for special effects. These can be mini-rockets that create serpents or partially filled tubes that, when ignited, produce a whistling sound – it’s like blowing across the tip of a straw, Grucci explains.

Workers fill fireworks from the bottom up through a hole in the top of the case. Spherical ones are made in halves, with one half covered with paper and flipped onto the other before being taped together.

Finish with a bang

Planning a firework show can take months – Grucci’s record-setting show in Dubai took about 10 just to plan and thousands of man-hours to set up.

Kowalyshyn says it takes about 80 man-hours to plan St. Albert’s Canada Day show, which is set to music. The New Year’s show takes about 30.

To prepare for tonight’s show, he and his crew will set up about 350 multi-shot mortars on Mission Hill and pre-load each with the necessary shells.

Back in the old days, you had to light fireworks with a road flare and reload the mortars mid-show, he recalls.

“The problem with reloading is someone had to hold a live firework with fireworks going off around them,” he says.

Today, crews load everything in advance and use electronic (and often computer-controlled) triggers.

Each shell is placed atop a black powder charge. When ignited, the charge (made mostly of oxidizers such as potassium nitrate) releases heat and gas, creating pressure to shoot the shell out of the mortar at about 122 metres a second and ignite the shell’s external fuse.

The fuse ignites the central charge, producing more heat and gas. The shell briefly contains that gas to create pressure, then breaches, releasing it as a supersonic boom. The stars ignite and fly, creating a brilliant pattern in the sky.

Risky business

Fireworks are explosive and must be handled carefully. There’s no smoking and no cellphones on site while Kowalyshyn and his crew are at work, and they set up a hill-sized exclusion zone around the launchers.

“Safety is everything in this business,” he says, which is why he sets up the most dangerous shells himself.

But the risk is part of the appeal for Kowalyshyn, as is the chance to perform for his hometown.

“To come home and play for your people? That’s just awesome.”

Scientific St. Albert

Like science? So do we! Scientific St. Albert looks at a simple, common phenomenon in the St. Albert region and explains it with the help of local scientists every other week.
Got a burning scientific question? Send it in to kma@stalbert.greatwest.ca.

Kevin Ma: Kevin Ma joined the St. Albert Gazette in 2006. He writes about Sturgeon County, education, the environment, agriculture, science and aboriginal affairs. He also contributes features, photographs and video.