Americans spent over a billion dollars on fireworks for last year’s Fourth of July, according to the American Pyrotechnics Association. Among the displays were firecrackers, rockets, cakes, and snakes. And then there were the sparklers, those slow burning sticks you either love or hate.
Sparklers are seen as the relatively harmless, family-friendly addition to Fourth of July festivities, or the lamest fireworks known to man. They’re a pyromaniacs entry-level toy or a more cautious person’s safe celebration. No matter how you feel, you have to respect the traditional role these hand-held fireworks have in Independence Day. But how exactly do they work?
The American Chemical Society (ACS) recently created an explainer video that shows sparklers in slow-motion and details the chemical reaction behind their dazzling displays.
In short, the ACS says sparklers can be broken down to an iron stick with four chemicals: fuel, an oxidizer, colorant, and a binder.
Fuels consist of powdered metals, including iron, titanium, ferrotitatium alloy, and aluminum and magnesium, which react with oxygen. To keep the sparkler burning, an oxidizer such as nitrate, chlorate, and perchlorate are added to the mix. When the oxidizers are heated, they decompose in a gas reaction that sends little metal particles – i.e., sparks – flying into the air.
The binder most sparklers use is dextrin, which keeps all the other chemicals help together and slows the chemical reactions to. Colorants such as strontium, magnesium, and copper can be added to elicit red, white, and blue sparks respectively.
Maybe most importantly, the ACS points out that, although the sparks aren’t hot to the touch, the iron shaft itself can still burn since it retains heat from the reaction. So, have fun this holiday but be sure to hold to cold end of your sparkler.