How science helps light up the sky on the Fourth of July

As America’s 250th birthday approaches, communities across the country are preparing for one of the holiday's most beloved traditions: fireworks.

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From dazzling reds and fiery oranges to vibrant greens, deep blues, and rich purples, fireworks light up the sky every Fourth of July, drawing crowds from all over. 

But those colors aren't created by chance, they're the result of science.

Every firework is created from metal salts. The colors come from a different compound that contains metal and non-metal atoms packed inside the firework shell. 

Chemicals like potassium nitrate, sulfur and charcoal are used to help the fireworks burn. 

Nitrates, chlorates and perchlorates provide oxygen for the combustion, while dextrin is utilized as a starch that holds it all together.

When the firework is launched and ignited, the intense heat causes the atoms in those compounds to produce colors.

As the atoms return to their normal energy state, they release light at specific wavelengths, producing the colorful displays seen overhead.

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For example, strontium compounds create bright red fireworks, while calcium produces orange-colored fireworks. Sodium is responsible for yellow bursts, barium creates green, copper generates blue, and a combination of strontium and copper can produce a purple effect.

Firework designers carefully mix these compounds together to create both the desired colors and dazzling visual patterns.

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So, whether you're watching a neighborhood display or a large-scale celebration, you’ll know that every colorful explosion is a combination of science.