What Makes Fireworks Burst Into Those Crazy Colors?

Every Fourth of July, the sky explodes with reds, blues, greens, and golds while people across America celebrate Independence Day. But have you ever wondered how fireworks get their colors in the first place?

Turns out, it's all about chemistry — and the answer is way cooler than you might think.

It's All About Metal Salts

Inside every firework sits a carefully planned mixture of metal salt compounds that determines what colors appear when it explodes. These aren't the same as table salt — in chemistry, a "salt" is any compound formed from metal and non-metal atoms. When these compounds are heated to extreme temperatures, the electrons inside their atoms absorb energy and get excited. As those electrons drop back to their normal state, they release that energy as light — and the specific wavelength of light they release is what we see as color.

Different metal salts produce completely different colors. Want red fireworks? That comes from strontium compounds. Brilliant greens? Barium. Those deep blue bursts come from copper compounds burning at just the right temperature. Yellow — one of the most common firework colors — comes from sodium, which is so reactive that even trace amounts of sodium contamination can flood a firework with yellow light and wash out other colors entirely.