Why Your Brain Likes Explosions

It's Sunday, July fifth. Last night I stood in a field with a few hundred strangers and watched things explode in the sky for about twenty minutes. And I loved it. Everyone loved it. People were cheering, kids were screaming, phones were out, and the whole crowd was staring straight up at what is, when you describe it objectively, a series of controlled chemical explosions detonated above a populated area. I've been watching fireworks my entire life and I realized last night that I've never once asked why we do this, where it started, or why the human brain interprets loud explosions and bright flashes as a celebration rather than a threat. The answers go back over two thousand years to ancient China, where the whole thing started as an attempt to scare away evil spirits by throwing bamboo into a fire, and then took a turn when an alchemist trying to create an immortality potion accidentally invented gunpowder instead. The technology meant to create eternal life created explosions. The earliest version of fireworks had nothing to do with celebration and everything to do with fear. Around 200 BC during the Han Dynasty, the Chinese discovered that if you threw bamboo stalks into a fire, the hollow chambers would heat up, the trapped air would expand, and the bamboo would explode with a loud bang. They called these baozhu (bow-JOO), which translates directly to "exploding bamboo," and they used them to ward off evil spirits. The belief was that the loud noise would frighten away malevolent forces, and for centuries, that was the entire purpose: make something loud, scare something invisible, feel safer.

Sometime between 600 and 900 AD, Chinese alchemists were experimenting with various chemical mixtures in search of an elixir of immortality, because that was a real thing alchemists spent centuries trying to create. One of them mixed saltpeter, sulfur, and charcoal together and produced a black, flaky powder that turned out to be extremely flammable. They had accidentally invented gunpowder while looking for a way to live forever, which is one of the better ironies in the history of science. When they packed this powder into bamboo tubes and tossed them into a fire, the result was dramatically louder and more powerful than plain bamboo. The first real firecrackers were born, and a monk named Li Tian, from the city of Liuyang in Hunan Province, is widely credited with developing controlled packaging with fuses during the Song Dynasty. A temple was later built in his honor, and every April 18th, people in Liuyang still celebrate his invention by setting off fireworks.

The Chinese military adopted gunpowder for weapons almost immediately, developing rockets, bombs, and signal flares. But the civilian population kept using the same technology for celebrations, festivals, weddings, and the Chinese New Year. The same chemical compound was simultaneously being used to kill people in battle and to celebrate births in the village next door. Gunpowder has always lived in that space between destruction and joy, and fireworks are the version of the technology where we chose joy. Gunpowder stayed exclusive to China for centuries before it began spreading westward through trade routes, diplomats, and missionaries around the 1200s. Marco Polo is often credited with bringing fireworks to Europe in 1295, though Europeans had likely encountered gunpowder weaponry during the Crusades a few years earlier. Either way, by the late 1200s, both the technology and the recipes for making it had reached Europe and the Arab world.

European royals immediately turned fireworks into a competition. Henry VII had fireworks at his wedding in 1486, and it was the first recorded royal fireworks display in England. From that point on, monarchs across Europe tried to outdo each other with increasingly elaborate shows. Queen Elizabeth I created a position called "Fire Master of England" for the person responsible for royal fireworks displays. King James II knighted his fire master after a particularly impressive show. Fireworks became a way for rulers to project power and wealth, because the ability to blow things up beautifully required expensive materials, skilled technicians, and a willingness to spend money on something that literally vanished in seconds.

Captain John Smith is said to have set off the first fireworks on American soil in Jamestown, Virginia in 1608. But the tradition we know today started on July 4, 1777, one year after the Declaration of Independence was adopted. John Adams had written in a letter to his wife Abigail that independence should be celebrated with "pomp and parade, bonfires and illuminations from one end of this continent to the other, from this time forward forevermore." He was off by two days on the date he predicted, but the vision stuck. The first Independence Day celebration in Philadelphia included cannon fire, musket volleys, and a fireworks display, all during an active war. The Revolutionary War was still being fought when Americans decided the appropriate way to celebrate freedom was to simulate battle in the sky above their cities.

And here's a detail that connects yesterday's episode to today's: the fireworks the founders watched were nothing like what you saw last night. In 1777, fireworks were one color: orange-yellow. There were no reds, blues, greens, or purples. Those colors didn't arrive until the 1830s, when Italian pyrotechnicians figured out that adding specific metals to the gunpowder mixture produced different colors. Strontium makes red, barium makes green, copper makes blue, and sodium makes yellow. The science of colorful fireworks is basically chemistry, and the Italians, who are still considered the world's best fireworks designers, turned what had been a noisy orange flash into an art form. The question I kept coming back to last night is why this works on us at all. Loud bangs and bright flashes are supposed to trigger your fight-or-flight response. Those are threat signals. Your nervous system is supposed to hear an explosion and tell you to run. And yet hundreds of people were sitting in a field last night smiling and cheering at exactly those stimuli.

Psychologists who study this describe it as a controlled threat response. Your brain registers the boom and the flash as potentially dangerous, which triggers a small burst of adrenaline and cortisol. But because you're sitting in a safe environment, surrounded by other calm people, your brain simultaneously recognizes that there's no actual danger. The combination of physiological arousal with psychological safety produces a thrill, a rush that feels exciting rather than terrifying. It's the same mechanism behind roller coasters, horror movies, and skydiving: controlled exposure to something your nervous system interprets as a threat but your conscious mind knows is safe. The pleasure comes from the gap between what your body feels and what your mind knows.

There's also a communal element that I think people underestimate. Last night, a few hundred people I've never met were all looking at the same point in the sky at the same time, gasping at the same moments, going quiet during the pauses, and cheering together at the finale. That kind of synchronized group attention is rare in daily life. We spend most of our time staring at individual screens. Fireworks are one of the few remaining experiences where a large group of strangers shares a single visual focal point and reacts together in real time. The shared reaction is part of the pleasure, and it's probably connected to the same communal instinct that made ancient Chinese villagers feel safer when they all heard the bamboo explode together. The bang started as communal protection against evil spirits. Two thousand years later, it's still communal. We just replaced the evil spirits with a Tuesday night in July.

And one last thing worth knowing: about 99 percent of the fireworks used in the United States are imported from China. The country that invented them two thousand years ago still makes almost all of them. We buy roughly 285 million pounds of fireworks per year, and the vast majority come from factories in Liuyang, the same city where Li Tian invented the firecracker during the Song Dynasty. The technology went from China to Europe to America and the supply chain came full circle back to where it started. So if this comes up in conversation, here's how to think about it. Fireworks started over two thousand years ago in China as exploding bamboo thrown into fires to scare away evil spirits. An alchemist searching for an immortality elixir accidentally invented gunpowder, which became both the most destructive military technology of its era and the basis for celebratory explosions that have continued ever since. European royals turned fireworks into a competition of wealth and power. John Adams called for "illuminations" to celebrate independence, and the first July 4th fireworks were set off in 1777 during an active war. The colors we see today didn't exist until Italian chemists added metals in the 1830s, so the founders watched orange-yellow explosions only. Your brain enjoys fireworks because the combination of physiological threat with psychological safety creates a thrill response, the same mechanism behind roller coasters and horror movies. And 99 percent of the fireworks Americans use are still imported from China, mostly from the same city where the firecracker was invented over a thousand years ago.

Stay informed, stay curious, and we'll see you Monday.