Strange Science · Chemistry
Why fireworks burn in colour
By the Strange Science desk · 6 min read
Every colour in a firework is a small chemistry lesson. When a shell bursts, metal salts packed into pellets called stars are heated until their electrons jump to higher energy levels. As they fall back, they release light at very specific wavelengths, a process known as atomic emission.
The colour recipe
Red comes from Strontium carbonate, green from Barium chloride, and blue, the hardest colour to make, from copper compounds such as Copper chloride. Sodium gives a strong yellow, which is why even a trace of it can wash out a carefully tuned blue. The oxidizer, often Potassium perchlorate, supplies the oxygen that keeps the reaction burning.
| Colour | Typical compound | Emission |
|---|---|---|
| Red | Strontium carbonate | ~606 nm |
| Green | Barium chloride | ~524 nm |
| Blue | Copper chloride | ~428 nm |
| Yellow | Sodium nitrate | ~589 nm |
From stage to sky
Stage pyrotechnics and flame effects such as the Explo X2 Wave Flame use the same physics at a smaller, tightly controlled scale, usually cued from a lighting console over DMX. Designers rehearse those looks virtually before anything is fired, as in Virtual SFX Lab Wave Studio. The modern display industry traces back to China in the Tang dynasty, and today Guinness World Records tracks the largest displays on Earth.
Further reading: Flame test on Wikipedia.
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