On the Fourth of July, fireworks illuminate the sky in dazzling displays of pyrotechnics. Fireworks are a marvel of chemistry, dating back to ancient China.
In China, around 600 to 900 A.D., the first known fireworks crackled in the sky. Originally created to ward off evil spirits, Chinese alchemists made these illuminating lights by combining saltpeter (potassium nitrate, a type of food preservative), charcoal, sulfur and other ingredients, creating an early version of gunpowder. When thrown into a fire, the mix would explode with a loud bang.
Gradually, Chinese gunpowder samples and the chemical formulas used to make fireworks began to spread across the Silk Road to European and Middle Eastern countries, which used fireworks to mark military engagements as well as festive celebrations.
Colorful explosions closer to what we see today at our fireworks displays came in the 1830s, when Italian inventors added metals like strontium, to make red fireworks, and barium, to make green fireworks. From then on, fireworks took on entirely new, vibrant lights and colors.
Today, the typical firework mixture consists of fuel, an oxidizer to provide the oxygen necessary for burning, and metal chlorides, which contain the chloride ion that help make the colors. Various chemical elements produce a wide variety of colors, such as:
- Sodium, as found in common salt, creates a strong yellow color
- Copper chloride creates blue
- Strontium chloride produces red
- Barium chloride is used to make green
- The element calcium creates orange
Other Uses for Barium Chloride
Barium chloride is also used to detect sulfates. A chemist may use barium chloride when presented with a water-based liquid of unknown chemistry. If the addition of barium chloride causes the solution to form a thick white precipitate (a solid that forms in a liquid solution), it can indicate the presence of a sulfate.
Barium chloride is also used in manufacturing aluminum alloys, in pigments and dyes, and as a water softener.
The CPSC suggests these safety tips when using fireworks:
Do:
- Do have an adult supervise fireworks activities. Parents don’t realize that young children suffer injuries from sparklers. Sparklers burn at temperatures of about 2,000 degrees – hot enough to melt some metals.
- Do keep a bucket of water or a garden hose handy in case of fire or other mishap.
- Do light fireworks one at a time, then move back quickly.
- After fireworks complete their burning, do douse the spent device with plenty of water from a bucket or hose before discarding it to prevent a trash fire.
- Do make sure fireworks are legal in your area before buying or using them.
Don’t:
- Don’t allow young children to play with or ignite fireworks.
- Don’t buy fireworks that are packaged in brown paper — this is often a sign that the fireworks were made for professional displays and could pose a danger to consumers.
- Don’t place any part of your body directly over a fireworks device when lighting the fuse. Back up to a safe distance immediately after lighting fireworks.
- Don’t try to re-light or pick up fireworks that have not ignited fully.
- Don’t point or throw fireworks at another person.
- Don’t carry fireworks in a pocket or shoot them off in metal or glass containers.
