Firework colors are created by different chemicals combinations — here's what determines 7 colors in your 4th of July show

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It may be Independence Day, but there's nothing revolutionary about the way your 4th of July fireworks are made.

Fireworks have been built from a mix of explosive powder, chemicals, and glue for ages. The earliest fireworks shows date back more than a thousand years.

But not all fireworks are built the same. You can't get a bright red firework to light up with the same elements inside as a blue or white one. That's because the color of a firework explosion depends on what kinds of elements are inside, from common metals to rarer minerals and even some salts.

Pyrotechnicians call these bursts of colored light "stars," and they're made of a mixture of fuel, oxidizer (to help fuel burn), color-producing elements (like aluminum or copper), and a binder (glue) packed inside a shell. That all gets fired high into the air before a time-delayed fuse spits fire onto the stars and they take off.

California-based pyrotechnician and electrical engineer Mike Tockstein, who's prepping the Los Angeles Coliseum for a 4th of July show, told Business Insider that it takes days of pounding, digging, wiring, and "well over 10,000 pounds of equipment" to set up.

Before you peer up into the sky this Independence Day, take a look at some of the common elements that are making your celebration possible.

Yellow fireworks are made from an element you might associate with the color white: Sodium.

You may think sodium belongs in your salt shaker. But burning-hot sodium produces a bright yellow explosion that's perfect for lighting up the sky.

Red fireworks come from a common element called strontium.

Strontium was used in the glass screens of a lot of old color TV sets, because it helped block x-rays from hitting us. The element has a yellowish color, but it burns red hot.

Green fireworks are a result of barium salts exploding in the sky.

Most green fireworks are made from barium nitrate, which is toxic to inhale, so it's not used for much else, though it can be an ingredient in grenades.

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