The chemistry behind a firework explosion:
The four main chemical ingredients needed to make a firework explode are;
An Oxidizer- Provides enough oxygen to facilitate the burn.
Fuel- Once combined with the oxidizer sets the stage for an explosion.
Colorant- Pellets containing gun powder and colorant are packed into the body of the firework. These are the elements used to make each color;
Orange- Calcium Salts
Bright White- Magnesium
Binder- Used to hold the mixture of the firework together. The most common binder used in fireworks is dextrin.
The Chemistry behind the patterns:
The pattern you see in the sky comes down to the construction of the firework’s shell.
For each pattern you see there is a specific arrangement within the body of the firework.
It comes down to the construction of the aerial shells inside of the firework. If you form a heart pattern it will explode into the sky in that shape.