National Nuclear Security Administration

Facts About Fireworks

July 3, 2016

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How do fireworks work?

  • Fireworks are the result of chemical reactions involving a fuel source, an oxidizer and a color-producing chemical mixture.
  • Color combinations are produced in the sky when various metal elements are heated, exciting electrons and releasing excess energy in the form of light.
  • Fireworks generate three forms of energy: sound, light and heat.

Here are a few fun facts about the energy of fireworks, and how they help make the Fourth of July so special:

There’s also a small cylinder with a lifting charge just below the shell, which is shot out of a tube. When the lifting charge fires, the shell’s fuse is lit and burns as the shell rises in the sky. The fuse then ignites the bursting charge when the shell reaches the right altitude, resulting in an explosion.

Learn more about this fireworks and safety from the Consumer Product Safety Commission, and about historical Independence Day celebrations from the Library of Congress.

  1. Americans have set off fireworks since the first anniversary of the Declaration of Independence. On July 4, 1777, citizens of Philadelphia had a spontaneous celebration where they lit candles and set off fireworks that John Adams described as “the most splendid illumination I ever saw.”
  2. Standard aerial fireworks are shells with four main parts:
    • a cylindrical paper container with string,
    • stars, which are cubes or spheres containing the chemicals needed for the reaction,
    • a bursting charge in the shell’s center containing black powder,
    • a fuse with a time delay to ensure the shell explodes high in the sky.
  3. Color combinations are produced in the sky when various metal elements are heated, exciting electrons and releasing excess energy in the form of light. The color you see is determined by the chemicals that burn at different wavelengths of light in the spectrum. Higher energy compounds (e.g. copper chloride) emit colors like violet and blue and lower energy compounds (e.g. strontium chloride) emit colors like orange and red.
  4. Fireworks are the result of chemical reactions involving a few key components -- like a fuel source (often charcoal-based black powder), an oxidizer (compounds like nitrates, chlorates that produce oxygen) and a color-producing chemical mixture. The oxidizer breaks down the chemical bonds in the fuel, releasing energy. Fire (either in the form of a fuse or direct flame) kick-starts the chemical reaction.
  5. The patterns and shapes of fireworks depend on how the stars are arranged inside the shell. For instance, if the stars are spread out equally in a circle shape inside the shell, you will see a similar design in the night sky.
  6. Fireworks generate three forms of energy: sound, light and heat. That booming sound you hear after the explosion is from the quick release of energy, which causes the air to expand faster than the speed of sound, causing a shockwave.