A Central Michigan University professor teaches the science of fireworks.
People of all ages have long been captivated by the brilliant colors and whizzing, popping sounds of fireworks. How are these displays created? Dr. Gabriel Caruntu, professor of chemistry and biochemistry at Central Michigan University, knows just what makes these colorful patterns erupt in the sky.
Ever since Caruntu was a child, fireworks have sparked his curiosity. Later, when attending college to earn a chemistry degree and again while in the military, he was given the opportunity to learn more about the processes involved in pyrotechnics, including those synonymous with the Fourth of July.
When working toward his graduate degree, though, Caruntu focused on areas other than conventional chemistry. “My graduate training was focused on physics, materials science, and nanotechnology, but this did not decrease my interest in fireworks,” he explains. “The chemistry of fireworks is complex and very interesting.”
With fireworks, chemical reactions, which usually take place in solutions, actually occur in a solid state. Another unique reaction in terms of chemistry is the release of high amounts of energy, along with the formation of large volumes of gases.
Students who are fortunate to take a chemistry class with Caruntu receive a behind-the-scenes look into the reactions that go into fireworks. Since such processes occur via a succession of oxidation-reduction reactions, a fundamental knowledge of thermodynamics and kinetics of combustion is needed in order to fully understand what’s happening.
To help students learn about what is going on inside fireworks, Caruntu runs demonstrative experiments. “These reactions mimic those involved in fireworks, such as the well-known ‘chemical volcano’ reaction,” he notes.
In this reaction, ammonium dichromate, an orange unstable solid, decomposes upon heating and releases green chromium (III) oxide, nitrogen, and water. As with fireworks, the reaction is initiated by applying external energy in the form of a flame or spark, ultimately releasing light and a large amount of energy.
During the process, the decomposition of ammonium dichromate creates chromium oxide flakes, which liberate and float above the solid due to the release of gases. This gives an overall effect of a volcanic eruption.
With his background in chemistry and pyrotechnics, Caruntu knows how to make fireworks and about their history. He explains that “fireworks were invented in ancient China and spread to Europe during the Crusades.” Explosive nighttime displays in different patterns, shapes, and colors have grown in popularity ever since.
Caruntu also emphasizes, “Fireworks are spectacular to watch but dangerous to handle without proper training.” Always use caution when handling fireworks and stay up-to-date on local regulations. For more safety information and tips, visit www.fireworkssafety.org. •