In this special July 4-themed episode, we’re talking about a staple of many people’s Independence Day celebration: giant explosions! Whether you love fireworks or hate them, you’ll learn something about where they come from and how they’re made with our expert Simon Werrett!
Guest bio
Simon Werrett teaches the History of Science at University College London. He taught at the University of Washington, Seattle from 2002 to 2012. He is the author of Fireworks: Pyrotechnic Arts and Sciences in European History (2010) and Thrifty Science: Making the Most of Materials in the History of Experiment (2019).
Transcript
ABBY:
Hey Maggie, when you think about the Fourth of July, what do you think about?
MAGGIE:
I’m definitely going out to the Workhouse and sitting down on the yard, in the grass. It’s pretty fun. And then watching the fireworks, even though it’s pretty loud.
ABBY:
So what does it feel like when you see a huge fireworks display?
MAGGIE:
Well, it feels like, how is it that sparkly? Or how’s it that bright? But also, how is it not killing us all? It’s really loud.
ABBY:
How loud?
MAGGIE:
Like your eardrums are being split apart loud.
ABBY:
Also, I feel like you can almost feel the concussion from the explosion in your whole body, if you’re close enough.
MAGGIE:
Yes. I have a feeling that fireworks aren’t just for the Fourth of July though. So I think that maybe you should take a closer look at fireworks On today’s episode of
MAGGIE AND ABBY:
Big if True!
MAGGIE:
Where I, Maggie,
ABBY:
And I, Abby,
MAGGIE:
explore the truth about big things. Today we’re talking about giant beautiful explosions in the sky, though not all fireworks are big. So here’s our quiz question to test your knowledge.
ABBY:
One of the most well known references to fireworks in the United States is in our national anthem, where we sing about “the rockets’ red glare and the bombs bursting in air.” During what war was the national anthem written?
MAGGIE:
A. The Civil War; B. The American Revolution; C. The First Seminole War; or D. The War of 1812?
ABBY:
We’ll tell you the answer near the end of the show.
MAGGIE:
Our expert today has written a whole book about the history of fireworks.
WERRETT:
My name is Simon Werrett. And I am a professor in the Department of Science and Technology Studies at the University College in London in the UK.
MAGGIE:
Thank you for talking to us today, Simon. To start off, what is a firework?
WERRETT:
That’s a great question. It changes over time, and fireworks have a very long history. So there’s been lots of different kinds. But I think the key thing is that they use gunpowder to create some kind of effect. So gunpowder is charcoal, saltpeter, sulfur; you mix them up, and it creates– it doesn’t actually, it doesn’t detonate, it doesn’t explode, but it burns very, very quickly. And depending on how you control that burning, you can produce power, and that can be used to drive a firework. So you have different kinds. You’ve got rockets, for example, everyone knows rocket fly up in the air and explode. And you’ve got fountains, so you have big plumes of sparks that come out the top of the firework which you stick in the ground. You’ve got wheels, so they don’t– you don’t see those so much these days. But we used to have Catharine wheels, which are a firework that spins around, you nail it to a post, and then it spins around and shoots out sparks. And they might have different effects, different colors, different sounds, they make cracks and bangs. I think everyone’s familiar with them. So there’s lots of different kinds. But the core thing is that is that use of gunpowder to make some kind of special effect.
MAGGIE:
When were fireworks invented?
WERRETT:
Unfortunately, it’s really hard to say because, roughly speaking, you’re looking at between about the ninth and the twelfth century, is when gunpowder is invented, discovered, if you like, and then by about the 13th century, so the 1200s, you have records that are probably fireworks. And, as probably everyone knows, the place where that happens is in China. So you start to see people talking about fireworks as being used in celebrations in China. And then over time they spread across the world. They end up in Europe in the 14th century, in the US in the 17th century. The problem is that the Chinese word for fireworks are the same as the Chinese words for colored smoke or colored powder. So they were making effects for festivals with colored smoke and powder. And then gradually gunpowder replaced those. But because the language didn’t change, you can’t tell when it moved to gunpowder. It’s not very clear. So so we know it’s it’s really ancient, they’re really old. But it’s really hard to actually kind of put your finger on and say the in that date is when they started using fireworks.
MAGGIE:
How did the fireworks become something that we associate with celebration?
WERRETT:
Well, they were always used to celebrate. So I think you can go all the way back to the really earliest records of kind of medieval Chinese fireworks. And they were used for things like celebrating the new year. And, and for a very long time, they had two big uses. So they were used for celebrations, in festivals and rituals and performances, these are in the theater as well. And then they also use them in war, military fireworks. So things like grenades and bombs were considered to be fireworks and, and rockets as well, actually. So they’ve always had that; they’ve always been used for both, but but that celebratory way of using them goes back to the very, very beginning. There’s something kind of just spectacular about seeing fireworks. So I think probably straightaway, people thought they could, they could be used in that way.
MAGGIE:
Is celebration the only thing they’ve been used for?
WERRETT:
As I say, they they got used in war so so there’s a nice old print of a, of a pyrotechnician that was made in the Renaissance. And it says at the top of it “arte at marte.” And that’s Latin for art and war. And on the, on the one side of the picture, you see all the implements of warfare that includes bombs and grenades and rockets that you’d fire at your enemy in a battle. And on the other side, you’ve got sort of peaceful versions of all those fireworks, which you would then use for celebrating the victory when you triumphed over your, over your enemies. And sometimes fireworks were recreations of battles. Pity the poor soldiers, they had to fight the real battle. And then they went home. And then they had to do it all over again in a kind of mock display for the, for their king, or lead. And then they did it with pretend fireworks with ones that wouldn’t cause any any harm. But fireworks have also been used for lots of other things. So in the 19th century, for example, there was a big, there was lots of efforts to invent new ways of using fireworks. So for example, they came up with life saving rockets. And it’s a pretty simple idea. But you wonder why no one had thought of it before. But you know, if you stick a line, a rope on the, on a rocket, and then you see someone out at sea, who’s struggling in a boat to maybe in a storm, you can fire the rocket out and get the line to them, and then tow them back into, into the, onto the beach. And they use them for signals. So when you make a map, you use a process called triangulation to figure out where everything is on the map. And to do that, you have to have signals that you can see from a long way away. And so they use rockets as the, as the signals. And you’ve probably seen people firing up flares, to signal that they maybe they’re in danger. And that is a firework, essentially. So So there have been lots of different, different uses for them. And I think people are always kind of inventing new ways to use fireworks over over time.
MAGGIE:
Is it dangerous to make fireworks?
WERRETT:
It’s a very good question. And the answer is definitely yes. So really, really incredibly dangerous stuff, gunpowder. You got to be super careful with it. And the thing that you have to really really watch out for is that you don’t produce any sparks when you work with it, because you might accidentally set the gunpowder off, and then it can explode. So if you look at how gunpowder was made, and how fireworks are made, you can see that the places where they make them are very, very special. Few years ago, I went to a wonderful place in Wilmington, Delaware, called Brandywine Creek. And there is an old gunpowder factory that was set up in 1801 by a French gentleman called Monsieur DuPont. And the DuPont Chemical Corporation has its origins in that family. And you can still see the gunpowder factory as it was in about 1800. And so they made gunpowder in buildings that were all set up along the river. And what they did is the side of the building that’s facing onto the river is made with wood, or it doesn’t have, it doesn’t have a side and then everything else is stone. So if somebody accidentally blew up the gunpowder all the debris would shoot out over the river and not into the rest of the factory, which is where it might set off even more gunpowder; then you have a real disaster. And all the buildings are very separated. Spread out. And they had to make them so they didn’t have any nails in the floor because the, if you had hobnail boots with, with metal in them, and you stood on a nail, you might produce a spark that could set fire to the gunpowder. So it’s all really, really carefully thought out. And the other thing that they did is they had to make fireworks and gunpowder a long way away from any towns, because if your gunpowder factory blew up, then you know lots of people could get good get hurt. And unfortunately, before the 19th century, lots of people did make fireworks and gunpowder in towns. And they, there were awful accidents. And sometimes, because I’m a historian of fireworks, one of the ways I know about people in the past who who made fireworks is because their, their house blew up. They made a mistake and the house blew up. And then they put a notice in the newspaper The next day. And then that’s how you know that they were there. And there’s no other records of them. So so it’s not very good for them. It was good for historians, it was not so good for the for the people who made them.
MAGGIE:
What makes fireworks colorful?
WERRETT:
Well, the chemical answer is that you have two ingredients that you need for that to happen to have colored fireworks. One of them is this is a substance called potassium chlorate, which is a chemical that has lots of oxygen in it. And so it lets your firework burn at a higher temperature than other kinds of fireworks. And if you add metal salts to the gunpowder mixture made with potassium chlorate, then the metal salts burn with that extra oxygen and then they produce colors. So potassium chloride is a horrible substance talking about accidents. So it’s very, very volatile, which means that it’s really hard to handle without it exploding. So the person that discovered it guy called Berthollet in the, in the 1780s. He did some experiments with it, and it blew up. And it caused catastrophe. So said, Okay, don’t do that anymore. But after about 30 years, people figured out how to make it a bit more stable. And then they started adding it to fireworks. So this is in the 1820s. And the first person who actually recorded fireworks made with this substance was in Philadelphia, in I think, in 1822, a guy called James Cutbush. And what he did is he put this potassium chlorate in his fireworks mixture. And then he added what he called nitrate of strontium. So basically a metal, a salt of a metal. And when you burned the firework, when you set it off, it produced a really nice glowing red flame. And after that, people use different kinds of salts to produce the colors. So if you use barium chloride, you get green. If you use sodium nitrate, you get yellow. If you use copper chloride, you get blue. So you add those salts, and that’s what gives you that intense color. So that’s the chemical answer to your question. But there’s also a kind of historical answer, because first of all, people have always thought that fireworks were colored. So if you look much earlier in the 16th, 17th century, people say, “Oh, yeah, our fireworks are colored.” And chemists say, well, they can’t have been colored because they didn’t know about potassium chlorate. They didn’t know about metal salts. But of course, you know, fire is colorful. So people saw in even in just the kind of natural color of fire, there’s reds and yellows, and blues and white, so, so people thought they were colorful, all the way through. But there was this moment, in the early 19th century, when people use chemistry to add color to the fireworks and ever since then they’ve got more and more chemicals to use and brighter and different kinds of color. So So what we see today is is very, very kind of techni-color fireworks compared to what people saw in the past.
MAGGIE:
What makes fireworks in all those cool shapes?
WERRETT:
That is another bit of clever engineering. And this goes back all the way back to that idea that fireworks were originally used for war and peace. So one of the things that people used to do was they used to fire something that looked like a cannonball from from a mortar. So it’s a bit like a cannon that’s facing upwards. And you put your cannonball in it, and then you shoot it at the enemy. And the cannonball is called a shell and the fireworks too. Kind of a nice, peaceful, playful version of that, is that you you, you make a tube and you put a big globe of wooden paper filled with gunpowder inside it, and you put it in the tube, and then you shoot it out the tube. And it goes up in the air very, very high, and then explodes. And all of the contents fan out into the sky. So what they do is they make a shell. And they put little pellets of gunpowder into the shell. And they’re called stars. And when the, when the shell gets as high as it’s going to go, there’s a little fuse, that sets it off, it explodes and all the shells fly out. So when you see the big spray of fire coming out in the sky, what you’re seeing is all those little pellets, shooting out from inside the shell. And then, depending on how you organize your pellet in the shell, you get different shapes. So if you arrange them as a little smiley face, or a heart shape, then when it explodes, it will shoot them out. And as they light up, they’ll produce a heart shape or a smiley face. It’s pretty hard to do. I think people have only been been putting those kinds of shapes in, in the last 20-30 years.
MAGGIE:
What’s the coolest fireworks display you’ve ever seen?
WERRETT:
Well, there’s so many different kinds of fireworks. And I’ve, I’ve studied the history for a long time. So I’ve I’ve seen stories about fireworks displays, hundreds and hundreds of fireworks displays. So so it’s quite hard to pick a favorite. But there is one that I thought is really impressive. And I’d love to know how they did it. So if you go on the internet, there is a website and it shows old news clips from, going all the way back to the beginning of the last century. And there’s a little there’s a little video, a little film that was made in the 1920s of a fireworks display, which they did at Crystal Palace, which is a big kind of garden in South London, quite near where I, where I grew up. And one of the fireworks that they do there is basically an animation of elephants made with fireworks. So if you’re standing on the ground, watching what you see, and it’s nighttime, it’s all completely dark. And then suddenly, you see the outline of an elephant made with fireworks with like little lights of little kind of pyrotechnic light. And then it walks across a field. And it’s really impressive. It’s really amazing. And you think, how did they do that in 1920, 1922. And what they had, presumably, was a big framework with hundreds and hundreds of little firework fire lights on it. And they lit them in or in an order that would make it seem like an elephant was walking across the field. And the elephant kind of raises its trunk and, and it’s really impressive. It’s really good. I’d love to see that today. So that’s one that always sticks in my mind.
ABBY:
Fireworks also show up in many important events in the history of the United States. In fact, they’re in our national anthem.
WERRETT:
That’s the rockets’ red glare. So that comes from the War of 1812 between the British and the Americans, shortly after independence, and the rockets that, that’s referring to are Congreve rockets. There’s a guy in London, whose father was the head of Woolwich Arsenal, which is where the British built basically, where they made fireworks in the 18th, 19th century. And he’d seen– British troops in India had seen that the Indian troops used war rockets that were really big, and very, very powerful. And they kind of, they were real, really tough to fight against. So what Congreve did is he said, Well, maybe I can make a version of those rockets. And then the British can use those initially to fight the French. And so he made these gigantic rockets, like, including the stick, they’re 30 feet long. So they’re really big, and they’re made with an iron body, and you fill it up with gunpowder. You put an explosive in the cap in the head. And then you– what they originally did is they use them to blow up French ships in the English Channel. And then they took them to America, to North America, and they use them in that battle. So they were firing volleys of Congreve rockets. And that’s the rocket that has the red glare in the, in the national anthem.
MAGGIE:
Hey, there’s the answer to our quiz question. The National Anthem, otherwise known as the “Star Spangled Banner,” was written by Francis Scott Key during the Battle of Fort McHenry in the War of 1812.
ABBY:
We’ve included in our show notes a few art pieces from the War of 1812 that show the bombs bursting in air and the rockets’ red glare. And we’ve also linked to a few more stories about the Congreve rockets. You can check those out at bigiftrue.abbymullen.org.
MAGGIE:
And that’s it for today’s show. As you go watch fireworks for the Fourth of July, or maybe you shoot off a few yourself, think about all the ways that fireworks are Big if True!
ABBY:
Big if True is produced by me, Abby, and Maggie. Special thanks to our expert guest, Simon Werrett. Our theme music is by Andrew Cote. Make sure you check out our show notes at bigiftrue.abbymullen.org for lots of fun extras, and Happy Fourth of July.
More info
- Special thanks to the U.S. Air Force Bands’ public domain music for all the patriotic music in this episode!
