Fireworks explode into the night sky, dazzling us with their brilliant colors and thunderous sounds. They can be shaped into different shapes and sizes, or they can be sent flying through the air, as is often the case in aerial fireworks like skyrockets. These fireworks are the result of a series of chemical reactions between three key ingredients: an oxidizer, a fuel and a color-producing chemical mixture. The oxidizer breaks down the chemical bonds in the fuel, which releases energy to create the explosion that launches the fireworks into the sky. Fire (from a fuse or direct flame) kick-starts the chemical reaction.
The color-producing chemicals in fireworks are typically metal flakes of different types. Some of the most common are magnesium powder and aluminum powder, which produce bright sparks; iron powder produces blue sparks; sodium salts provide yellow; strontium or carbonate add red; copper salts give a firework its blue hue; and chlorine and sulfur produce green. The addition of these chemistries to the explosive fuel of black powder creates fireworks with distinct colors.
Once the oxidizer and fuel are combined in the how to store fireworks, the final step is to add the sound charge and a time-delay fuse. The length of the fuse determines how long it takes for the chemicals to reach their apogee, or peak height. Once they do, the explosion causes the bursting charges in each break to ignite and launch the stars into the sky.
Stars are also the primary components of the more complex multi-break shells that make up most of what we see in an outdoor fireworks display. These stars are contained in separate cardboard compartments within the break, and each one has its own bursting charge. When the time-delay fuse burns through, it ignites the bursting charges, which then throw out stars in a pattern that mimics the original design of the firework.
To make these fireworks, pyrotechnic engineers mix carefully measured ingredients into a dough-like consistency. This mixture is then stuffed into mortars, which are made of fiberglass-reinforced epoxy or high-density polyethylene. The mortars may also contain other materials that enhance performance, such as barium nitrate to produce green, and charcoal or other forms of carbon for orange. The finished product is then loaded into a shell, and the fuse and time-delay are attached to the firing end of the fireworks. Fireworks can be dangerous, even the smallest fountains or spinners, so never lean over them when lighting and always back up after they’re lit. Cotton clothing is better for avoiding burns than synthetic fabrics, and it’s best to avoid touching fuses directly in order to prevent accidental detonation. If you’re planning to use fireworks, read the igniting instructions on the package to learn how to do it safely.