Chemistry Lights Up Fireworks
Every Fourth of July, the nighttime skies across the country light up with amazing fireworks displays. But what exactly puts the sparkle and bang into a fireworks show? A little bit of chemistry has the answer.
Each firework launched is a carefully crafted shell packed with a combination of chemicals and fuel to create different effects and colors.
“You can get a wide variety by modifying chemical reactions and then using physics to get them into the right place in the air at the right time,” said Chemist Joseph Domanico of the International Fireworks Seminar Society.
Colors can be modified, brightened and enhanced using specific chemical reactions.
A little bit of clever engineering can also manipulate the sound a firework makes. Whistling fireworks, for example, are made with a narrow tube. A special mix of chemicals is packed tightly into half of the tube so that there are no air pockets. When the firework is lit, the empty part of the tube vibrates making a whistle sound.
Beyond the basic firework is a dragon egg – or crackling micro-star – pellets containing metal powders combined with other chemicals that first burn brightly, and then explode with a sharp crackling sound.
Fireworks have been around for thousands of years. Legend has it that the first firework was invented by accident. A Chinese cook spilled saltpeter – an ingredient previously used as a type of salt flavor for food – into a fire while cooking and saw that it produced a unique flame.
Advances in science and technology have helped make fireworks bigger, brighter and louder than ever before.
Inside Science Buzzwords:
- Pyrotechnics - The science of combining materials that produce chemical reactions resulting in heat, light, gas, smoke and sometimes sound.
- Firework - An explosive pyrotechnic device containing gunpowder and a combination of chemicals that explode when ignited for entertainment purposes.
Inside Science Extra: What Gives Fireworks Their Colors?
White - Aluminum
Red - Strontium chloride
Orange - Calcium chloride
Green - Barium chloride
Blue - Copper chloride
