Happy Birthday America! Learn the Chemistry of Fireworks
Craig the Rocket Scientist
July 5, 2012 I was going to write an in depth review on human vs alien kick-boxing in honor of our forefathers, followed by a “Han shot first” review because beating intergalactic aliens up inevitable leads to shooting them as well. (Note: Please do not beat up or shoot human aliens, only alien aliens… accept Alf, he’s cool) But Mrs. Craig thought it would be better I talk about something a little more mainstream like the chemistry behind fireworks.
So first things first: Fireworks are actually controlled burns of chemicals that release energy stored in chemical bonds. When these burns occur they create three main by products: heat, light, and by products (carbons, water, etc.). For crowd-pleasing purposes we like to focus on the light aspect and by putting this reaction in a closed container we cause an explosion which produces a satisfying boom; unless you’re a dog then you think the world may be ending.
So how do we make all the different colors? By burning different chemicals of course!
- Red = Lithiums and carbonates
- Orange = Calciums
- Yellow = Sodium
- White = metals like aluminum or magnesium
- Green = Barium
- Blue = Coppers
- Purple = mix red and blue compounds
Fun fact: we use these same colors to help us decode what nebulas are made out of! By seeing their colors we can tell if a gas cloud is mostly hydrogen, helium, or some other base material.
Now here comes the rocket science: Aerial shells, sometimes called mortars, come in two types. One functions like a gun where pressure from an explosion drives the powder upwards, the other is a two stage rocket. Regardless of the launching method once the charge is at altitude the powder explodes and the audience is thrilled.
Pay attention because this is where people get hurt. These charges are based on a fuse, so the altitude they are when they explode is irrelevant. That’s why if your mortar doesn’t make it out of its tube it’s best to seek cover for a few minutes.
This is the part of the post where I tell you not to blow yourself up or something like that… so yeah, don’t be dumb. Also trying to build your fireworks is a bad idea, even the pros are usually missing a finger or two.
And now for something completely different:
http://www.youtube.com/watch?v=OfPWpEKhgfk
