Strontium Nitrate And Barium Nitrate, The Fuel In Fireworks
ERIC WESTERVELT, HOST:
Ladies and gentlemen, light your fuses.
(SOUNDBITE OF FIREWORKS)
WESTERVELT: Fire in the hole. Tonight, as you oooh and awe to brilliant reds and whites and blues bursting in air, you might wonder about the artistry and chemistry that go into those awesome displays. Harry Gilliam can explain. He's the founder of Skylighter in Round Hill, Va. They supply material for the manufacture of all kinds of pyrotechnics. Harry Gilliam joins us now. Welcome to the program.
HARRY GILLIAM: Thanks.
WESTERVELT: Mr. Gilliam, first of all, so how do you make all those wonderful colors? What are the building blocks?
GILLIAM: The colors stem from different elements, so, for instance, strontium - the element strontium - produces red. And it will always - we don't just use strontium. It comes in a composition; for instance, strontium nitrate. Greens will come from something called barium nitrate. Blue typically comes from copper. And so the different colors are all achievable by elements that we use that are in different chemical compositions that we use in pyrotechnics.
WESTERVELT: Mr. Gilliam, is there an exact recipe to this or is there some flexibility and creativity allowed in making these fireworks?
GILLIAM: Well, there's both. If you're smart and if you're just starting out, you really ought to use a recipe and it's sort of like cooking. You'd start with a cookbook and you'll have a good recipe. You'll have a list of the ingredients. You'll have an instruction for what the sequence is - what to do first, what to do next - but once you know what you're doing, there's a lot of flexibility. So, for instance, when you and I look at what we call an aerial shell, which is that thing we see up in the air that explodes and throws out those little points of light with different colors, I may have made an aerial shell that had red points of light last week and if I want to do it green this week then I can just substitute one chemical typically and change the color of that. Or I can have the stars, which are those little things we see come out of the shell, I can have those actually change colors. They may come out of the shell as green, but over a period of a few seconds they may change to red and then end in the silver color. So we can do all kinds of things. If we can think it up, we can usually do it.
WESTERVELT: Tell us your chef secret. How do those stars change colors?
GILLIAM: (Laughter) Well, it happens a couple of ways, but one simple way is we roll stars. We make them round and we do those in layers, just sort of like we roll a snowball up in the front yard for a snowman.
WESTERVELT: You also sell the materials to hobbyists who make their own fireworks. It's a little bit alarming. Is that allowed everywhere?
GILLIAM: Depending on where you are, it's allowed federally just about everywhere in the country. And inside the set of federal regulations there are a number of clubs in this country where people join these clubs, sort of like we have high-powered rocketry clubs. And people will join those clubs and they can go and make fireworks legally. They can get instruction and learn from people who know how to do it and learn how to be safe and basically keep themselves alive and out of trouble. And then they can shoot those fireworks, typically in a club environment, a lot of times for a whole weekend. These clubs will get together and guys will make fireworks and then have a display at the other end of the weekend. So there are controls on it, and depending on what state you're in, and even what county and city you're in, it's legal. In other places it's not legal, but federally, the U.S. government says yep, you can make your own fireworks if it's for a hobby.
WESTERVELT: So what are your plans for tonight? Do you get the night off or no?
GILLIAM: No. I've got a fireworks display tonight. We're doing a fundraiser out near Round Hill where I live and probably got about 500 people coming to it and going to have a really pretty display tonight.
WESTERVELT: Harry Gilliam - he's a pyrotechnician and founder of Skylighter in Round Hill, Va. Thanks so much and happy Fourth.
GILLIAM: Happy Fourth to you, have a good time, stay safe.
(SOUNDBITE OF FIREWORKS)
WESTERVELT: This is NPR News.
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