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A look at the science behind fireworks

4th of July is here, ready for the fireworks?
4th of July is here, ready for the fireworks? 01:56

MIAMI – An estimated 16,000 fireworks shows will be held across the country Monday night. But how do pyrotechnicians create all those beautiful shapes and colors in the sky?

A symphony of sights and sounds. But the magic behind fireworks is actually just science. 

"You're seeing chemistry in action," said Paul Smith.

Smith is president of the Pyrotechnics Guild International.

"The basic composition of a firework material is it has to have an oxidizer and a fuel," he said.

Basically, different colors require different chemicals.

"Strontium is a predominant one used for red, barium is often the key component in green color situations, copper is for blue," Smith explained.

Each firework shell has to be precisely packed and timed to the second to synchronize with the music. 

And even the grandest of fireworks shows, like the Macy's Spectacular, uses many of the same techniques as local public displays – just bigger. This production involves 48,000 shells, creating 17 unique patterns in the sky.

"This particular one will get thrown out in the shape of a happy face," said Macy's fireworks designer Gary Souza.

Souza showed us how the small frame in his hand can create massive shapes in the sky. 

"Making shapes with fireworks has become more and more of an art, in a sense that you have to strategically place the shells, the stars within the shell," he explained.

An awe-inspiring American tradition powered by science.

And a tip from the pros. They say the best seat to watch the fireworks is usually not close up. They say give yourself a little distance so you can take in the entire display.

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