The weekend is vastly approaching and if you haven’t noticed already, firework shops are booming all over town. Plenty of parties, picnics and towns will be entertained by them on this holiday weekend. Have you ever wondered what makes fireworks colorful? What makes them whistle, boom, and crackle? Chemistry.
The colors seen in most fireworks today are fairly recent phenomena. Before the 19th century colors were limited to golds, silvers, and oranges. Advances in chemistry have led to the addition of various agents to the fuels and oxidizers to produce the vibrant colors we see in the sky at modern displays.
Black powder is the propellant favored for fireworks. It is simply a mixture of charcoal, sulfur, and potassium nitrate, and is most frequently used to make fuses, lift charges, and break charges.
Many fireworks are named for the effect they create. There are salutes, which are shells that explode violently, producing a loud report with very little visual effect other than smoke and a bright flash. Titanium salutes are similar except the report is accompanied by a large cloud of white sparks. Screamers are the shells that whiz with a screeching sound as the gain altitude.
The colored effects are often named after flowers like chrysanthemum, dahlia, and peony. The chrysanthemum is a spherical hard-breaking shell in which the stars produce a tail. A dahlia shell produces brightly colored stars that fall from a soft break. A peony is a spherical hard breaking shell in which the stars do not leave tails. There is a willow shell that produces trailing stars that droop and form a pattern similar to a willow tree.
The colors can be created by metals, inorganic compounds, or organic compounds. Titanium and aluminum are two metals used in the fuel to create white sparks. Lampblack, a form of carbon, creates golden sparks. Iron is used to create the branching sparks that resemble palm trees in the sky. Barium compounds create green, calcium compounds produce reddish-orange, copper compounds burn blue, sodium compounds flare yellow, and strontium compounds are responsible for red. Now you can impress your friends and family with your new-found knowledge. We wish you all a Happy 4th of July, as you watch the fireworks fill the sky!!