The magic (and science) of fireworks

Fireworks are probably one of the first things that come to mind when one thinks of the Fourth of July, but many people may not realize how much science and technology go into those pretty sparks in the sky.

Fireworks date back to the early ninth century Chinese Tang Dynasty, where fireworks were used in celebrations. The Chinese people reportedly believed fireworks could expel evil spirits and bring about luck and happiness.

Chemistry

Colored fireworks developed from earlier (about 202 BC) Chinese application of chemical substances to create colored smoke and fire. Fireworks were produced in Europe by the 14th century, becoming popular by the 17th century.

There’s a lot of chemistry that goes into making fireworks light up the sky in all those pretty colors. Each streak of light you see in one of those giant bursts comes from a single pellet, called a “star” that contains:

„ A fuel to make the pellet

burn; „ An oxidizer — a compound which produces (usually) oxygen to support combustion of the fuel; „ Color-producing chemicals; and „ A binder to hold the pellet together.

Most pyrotechnics use black powder, which has been around for thousands of years, to launch the stars into the sky and increase the size and force of the explosion.

To add color to the explosions, we turn to everyone’s favorite — the periodic table of elements. Various elements or compounds are added to the mixture to create the following colors:

„ Red–strontium(intense red), lithium (medium red);

„ Orange — calcium;

„ Yellow — sodium;

„ Green — barium;

„ Blue — copper;

„ White — titanium, aluminum, beryllium or magnesium powders;

„ Indigo — caesium;

„ Violet — potassium, rubidium (violet-red); and

„ Gold—charcoal,ironor lampblack.

Improved technology and safety

The chemistry part hasn’t changed very much, but technology definitely has. From more sophisticated launch systems to improved safety to bursts shaped like flags, hearts and smiley faces, technology has allowed the pyrotechnics industry to create bigger, better, safer and more impressive displays.

Fireworks fuses used to be lit by hand, which was very dangerous and resulted in many injuries and deaths. These days, the shells are loaded into mortar tubes, placed, and then lit remotely. There are even apps for phones and computers that crews use to run the entire show from a safe distance. These programs allow for precise timing and can incorporate synchronized music with the launching shells.

Costs of fireworks displays

The cost of a typical city Fourth of July display can be anywhere from $10,000 to $50,000, with the average price tag around $25,000. However, the bigger the display, the bigger the cost; a few shows cost more than $100,000. Permits and insurance are extra, by the way.

The Macy’s Fourth of July Fireworks Spectacular, which generally averages around 1,600 shells fired per minute, burns through upwards of $5 million dollars to wow its estimated 3 million live spectators and another 5 million viewers watching from the comfort of their living rooms. And there’s no dress rehearsal.

Here's wishing everyone a safe and Happy Fourth of July.