The Fourth of July is just around the corner and we wanted to take a moment to dissect the science behind the highlight of the summer – you know what we’re talking about – fireworks!
A delight for people young and old, fireworks have been lighting up the night’s sky since the 9th- century medieval Chinese Tang Dynasty – that’s a long time ago. But how do they work?
To break it down to the most basic terms, a firework is simply a container that holds a number of explosives attached to a delayed fuse. These containers are usually filled with little balls of colored explosives called stars that bring on the oohs and ahhs, but only after a specific amount of time has passed – this is how fireworks can reach the heights of the sky before they explode.
Once the delayed fuse gets close enough to the firework it ignites a charge that then lights the explosive – which spreads out the charge (and little balls of color or stars) through a high pressured gas cloud.
The Chemistry of Colors
Inside every star, or little explosive sphere, is an oxidizing agent, fuel, metal that acts as the color, and a binder that holds everything together. The metal you choose to coat the stars determines the color you see in the sky. For example, calcium salts burn orange, and sodium salts burn yellow, but if you burn copper, it’s a beautiful blue-green color.
Modern-day fireworks can be really simple, or crazy intricate – mimicking certain facial expressions (smiley face), geometric shapes (a heart or star, for example) or even an animal. More complex color and explosive actions like these are achieved when fuses are strung together, and the stars are carefully organized, building different chambers of gunpowder in the firework. These grouped aerial shells produce the series of light, color and sound we’ve all come to love.
These are the fireworks that shake us to our core. Once you see that bright flash of light, there
is sure to be a giant booming sound to follow. That’s caused by a sonic boom that happens as the gases inside the firework expand faster than the speed of sound! Crazy!
Wishing you a fun and safe Fourth of July from everyone at Remke. Get out there and enjoy your time with friends, family, and fireworks!