What Causes Fireworks to Explode?

The cause of a firework's explosion is a process known as oxidation. To have a successful fireworks show, there needs to be oxygen, different kinds of metals and a creative spark. However, the first two are what really are necessary for a firework to explode.

Metal is ground up into tiny little fragments and then packed into the firework casing. They grind up the metal because, when large chunks of metal are oxidized, it creates a shield around the inner parts of the metal. This prevents complete oxidation. By grinding the metal into small pieces, oxidation can be almost instantaneous rather than a slow, tedious process.

When the pyrotechnic launches the firework, it shoots high into the air. When the firework explodes, the metal scatters around. As the metal and the air mix, the metal begins to oxidize. The more it oxidizes, the more reactive it becomes. This reactivity is what produces the light. They become so hot that you see all of these different, marvelous colors. When the light disappears, it's because of the metal being completely oxidized.

For small fireworks and ones that are on the ground such as firecrackers, there is gun powder used. Gun powder explodes and when this happens, gives off a considerable amount of oxygen. This oxygen then mixes with the metal pieces in the firecracker which, in turn, results in light as described above.

The big question is how do all of the different colors appear? That's caused by different metals. Depending on what type of metal you use determines what color the light will be when it appears. Below is a list of the metals and the subsequent color that is creates.

• Red – Strontium and lithium
• Orange – Calcium
• Gold – Incandescence of iron, charcoal or lampblack
• Yellow – Sodium
• Electric White – Magnesium or aluminum
• Green – Barium plus a chlorine producer
• Blue – Copper plus a chlorine producer
• Purple – Strontium plus copper
• Silver – Aluminum, titanium or magnesium powder or flakes

It should be noted, though, that typically, it's not just aluminum in a firework when there is silver. Many fireworks have mixtures of these metals to create the many different colors that pyrotechnics employ in their grand firework demonstrations.