Long before chemistry was a formal science, humans were experimenting with substances to solve problems, cure illnesses and make money. In his book "The Age of Alchemy: How Early Innovators Shaped Modern Chemistry" (Profile Books, 2026), author Kit Chapman, a science journalist and honorary researcher at Falmouth University in the U.K., traces how this ancient, protoscientific tradition shaped the world.

From our ancestors' early use of fire to some accidental — and disastrous — pyrotechnics in the 14th-century French court of Charles VI, Chapman reveals how early innovations across the world paved the way for modern science.

Live Science spoke with Chapman about his book, which has been short-listed for the 2026 Royal Society Trivedi Science Book Prize.

Read an excerpt: 'These were harder than any other blades, cut sharper and cost more': How ancient Sri Lankans created steel of legends by harnessing monsoons

Hannah Osborne: The book is full of brilliant historical anecdotes that bring all of these alchemy breakthroughs into context. What was your favorite one and why?

Kit Chapman: I mean, you can't go wrong with a man trying to turn his own urine into gold, I think. Hennig Brand [who accidentally discovered phosphorus in the 17th century] was one of my early touchstones. I've known about this story for a while. I've always thought, "How can I get this into a book? What's the link?" Obviously alchemy provides this fantastic base. He bankrupted two wives to try and fund his 1,500-gallon [5,700 liters] urine habit — and then he gets something [phosphorous], against the odds.

This is the first element we can actually put a name to. This is the first person we can say actually discovered a chemical element, and it's an alchemist in the purest sense of the word. Then, of course, he tries to keep it secret. He sells it, eventually, to a friend, and his urine goes on tour around Europe, showing the kings and queens this glowing pee, before suddenly, [chemist and philosopher] Robert Boyle actually works out exactly what's going on.

That, to me, sort of encompassed everything I was hoping for in the book. There's a fantastic story there that's about human connection. There's the unraveling of mythology, and theology and belief, and starting to look at science. But there's also real practical stuff going on there. He didn't know what he was doing. He just didn't know why he was doing it, and that I found fascinating.

HO: You make the point that these people weren't thinking, "Oh, I'm going to do chemistry." How important is that for understanding how these early innovations shaped modern knowledge of how things work?

KC: I think that's essential. We often look at science as something separate from the real world, and one of the things that I really wanted to do with this book was to illustrate that science is going on in every profession. It's going on in every home, continuously; it's going on in our bodies continuously. It's everywhere.

Science is a way to understand what's going on in the world. It is not a separate thing from culture, from belief, from trade, from globalization, from discovery, from just getting on with life. I wanted to bring in the potters, the weavers, the bakers, the urine salesmen — which was an entire thing that I didn't really know I had to go down. I found it fascinating.

And, of course, [there are] artisans. When we start looking at the first actual chemistry that's being done, it is people trying to create beautiful works of art, perfumes, things like that. It moves away from survival and into this ecstatic beauty, and that, to me, encompasses what I love about the history of science. It's bringing all of these threads together and making discoveries not necessarily where we think we're going to find them.

HO: You mentioned the beauty of it all, and the perfume. One of the chapters I really enjoyed was the first chemist who was a female perfume maker in ancient Assyria.

KC: Tappūtī Bēlet-ekallim. The fascinating thing is that the only reason we know her name is that she put it down in cuneiform. She wrote it down. She may well have been a slave; perfume makers were often slaves. She was certainly a woman who was working in the palace. She was working with another woman whose name, unfortunately, we've lost to time.

What I find fascinating is that we now have this person who was one of the working class, one of the underdogs, slaving for a week to make this potion that she wrote down because the recipe is incredibly detailed. And we remember her name, but we have no recollection of the lord or lady that she was actually making it for. It's kind of class warfare throughout the centuries.

HO: I found the extreme sort of secrecy really striking — that so many of these ancient texts were lost because they were being hidden. But then you also have the fall of civilizations, so we've lost all this knowledge.

KC: It's this combination of, as you mentioned, hiding the recipes because they are trade secrets. If you look at the first alchemy book that we actually know of — "Physika Kai Mystika" — it literally translates as "natural and secret questions" or trade secrets. These were craftsmen, and, of course, they didn't want to share it with rival craftsmen. If you've got a really good recipe for making something look like gold, you want to keep that to yourself.

They use these code words — and that went all the way through into what we think of as alchemy, that sort of Renaissance period where they're talking about taking the fiery sword from the belly of the dragon, which is just wonderful and descriptive.

But you also have things like Emperor Diocletian destroying the texts in Alexandria in 300 A.D. Why did he do it? Because it was a matter of survival for him. Twenty-five of his predecessors were murdered by their own guards or died of plague and things like that ‪—‬ horrible fates. He wanted to avoid that, and the idea that [someone] could turn something into gold terrified him. It would debase his currency, so it always brings in that politics. It brings in human nature and human curiosity.

HO: Do you think there are still things we're yet to discover from alchemy from the past?

KC: Yeah, without question. Whether or not we're going to discover some kind of new, groundbreaking technology that's going to change the world, I can't see that happening. But the one thing we could see is the use of natural products in a way that we hadn't necessarily thought [of].

A great example of that is [Nobel Prize-winning chemist] Tu Youyou and the discovery of artemisinin compounds [from the] qinghao [plant], which comes from a Chinese alchemist's herbal remedies book, essentially 1,700 years ago. The fact that the best defense we have against malaria, the best antimalarials possible, comes from this ancient alchemical source indicates that there's probably more to find.

There is almost certainly more to find in terms of how they [ancient alchemists] used recipes, how they would try and make gold. Their understanding of the world is something that we don't necessarily have a full grasp of, and we're still piecing it together. There's some wonderful work being done by Matteo Martinelli and others looking at the history of, particularly of Western alchemy emerging in Egypt.

We also have things like Greek fire. We have a pretty good idea how they did it, but if you're looking for what the exact recipe [is], we're still not 100% sure.

HO: It's interesting now, watching modern equivalents taking place. We still, to an extent, try to guard our own knowledge.

KC: Yeah, we do, and I think it's actually a pernicious thing in science. We have this publish-or -perish mentality, which is that if we don't get the paper out first, obviously we lose the patent, but wider than that, we lose the kudos. There's this kind of necessity to kind of hide things. You hear about all kinds of shenanigans ‪—‬ a reviewer delaying a paper until their paper comes out, things like that, all this kind of naughtiness going on.

We've got to recognize that science has moved on certainly from the "Great Man" idea. We're now working collaboratively in teams. That is the only way that modern science gets done. The second, if there is one lesson from the book, it's that if you try and hide science, you delay progress.

The moment you actually start spreading ideas, the real ignition for me for the Renaissance and for what becomes chemistry, is the printing press. It's the fact that ideas can then be shared and accessed by everybody. The moment we start realizing that science is a global endeavor, that everyone can do it ‪—‬ man, woman, child, it doesn't matter your nationality, [it] doesn't matter your ethnic ethnicity, it's for everybody ‪—‬ the sooner we're going to start seeing some major progress that we otherwise wouldn't make.

HO: We see loads of the advances in chemistry and alchemy within civilizational melting pots. What were some of the biggest surprises to you when you were researching the book?

KC: One thing that really annoyed me was, looking through textbooks, you can look at who made zinc, and you come up with a name that came from the 1700s, or how platinum was discovered — that's a fantastic example. Platinum was discovered by a conquistador who noticed that some natives were wearing platinum. But, of course, he didn't discover it; it was discovered by the Indigenous populations.

The amount of science that came out of Mesoamerica, Central America, and the way that science was also being developed in India, it's just kind of completely overlooked. If you look at the traditional story of science, we talk about Europe. Occasionally, we might bring in China. But India, Africa, Mesoamerica, South America, North America ‪—‬ every single continent was having scientific discoveries and developments.

They weren't necessarily developments that we think of in terms of leading to chemistry, but they were dealing with social problems that they had at the time. They were tackling what was in front of them, and we always need to remember when we're looking at history to look at the context of the discoveries.

HO: Which breakthrough did you think was most impressive in terms of the materials or facilities that were available?

KC: One thing that I found sort of striking was, there's a chap called Paracelsus who is absolutely fascinating, absolutely bonkers. Paracelsus is, for me, the archetypical alchemist because he was certainly trying to revitalize medicine and get rid of humor theory and come up with all these ideas. [Editor's note: Humor theory is the idea that human health and temperament were related to four fluids in the body — black and yellow bile, blood and phlegm.] But he also believed that mermaids were real and that they were just out to steal men's souls.

He was a drunk, he had a broadsword, and yet he's the guy that was able to combine what we think of as the traditional herbalist role and the doctors. At that point, doctors weren't even touching patients. They believed that the true skill of a medical man was that you didn't even need to examine a patient; you could just sort of look at them and you'd know what was wrong. He [Paracelsus] was able to say, "No, that's not right; you need to actually test things, and you need to try things." The moment we actually combine those two different threads together is when we actually started to get what becomes of modern medicine. The number of lives that saves is incalculable, so I think that that's one of the great moments.

The other one that always comes to me is Antoine Lavoisier in the French Revolution. He made several great discoveries — the fact that matter can only be changed; it can't be destroyed [at least at low energies]. The idea that if you take something, then obviously there's got to be components to that; you're not making it out of thin air. And coming up with a list of elements in the French Revolution or just before the French Revolution, unfortunately dies, from the guillotine [when Lavoisier was executed].

That, for me, was when we started to get true chemistry. That's when all of the magic is dispelled. I think he [Lavoisier] is, for me, the French equivalent of Isaac Newton. He's incredible.

HO: For you personally, throughout researching and writing the book, what was your biggest takeaway and what was the biggest surprise?

KC: My biggest takeaway is that science happens everywhere continuously through everyone. I traveled around the world for this book; I went to pretty much all of the continents. I didn't go down to Australia; that's about it. Wherever you go, there are discoveries being made. There are people who are trying to make their worlds better.

Science is not for this elite group; it's for everyone. One of the things I try to do with this book is to show people that even if you think that science isn't for you, it absolutely is; you're doing science continuously.

There've been so many [surprises]. One of the things — this is purely because of the way that I was taught and these inherent biases that we have — but it's so easy to overlook the role of women. When you start delving into the role of women in science … You've mentioned Tappūtī; we also have Mary the Jewess. Throughout the Renaissance, we have people like Caterina Sforza and [the] very famous Queen Christina of Sweden, which I didn't mention in the book because I just didn't have space.

The one shocker for me is this book "The Secrets of Isabella Cortese," which was a man pretending to be a woman to sell his science book. For me, [it] just kind of unravels this whole idea that science isn't for everyone.

This interview has been condensed and edited lightly for clarity.

About 2,500 years ago, people in what is now India and Sri Lanka were manufacturing an exceptionally high-quality type of steel. Wootz steel was extraordinarily strong and sharp, and they exported it globally — in the Middle East, it was used to forge the legendary Damascus blades. But around A.D. 1100, it vanished, and the knowledge of how these ancient people forged such high-carbon steel was lost.

In this excerpt from the book "The Age of Alchemy: How Early Innovators Shaped Modern Chemistry" (Profile Books, 2026), author Kit Chapman, a science journalist and honorary researcher at Falmouth University in the U.K., reveals the extraordinary story of Wootz steel and the experiments that finally showed how it was created using furnaces powered by monsoons.

Kit Chapman interview: 'His urine goes on tour around Europe, showing the kings and queens this glowing pee'

During the Industrial Revolution, it became clear that something far stronger [than iron] — steel — was needed. Victorian engineers had started to build larger projects than anyone had ever seen, and were using cast iron for their structures, such as the first metal bridge, at Ironbridge in Shropshire. But cast iron was too weak. In 1847, a cast-iron railway bridge over the River Dee collapsed less than a year after it was opened.

If the world was going to modernise, it had to come up with a better material. Steel was the obvious answer, but how did you get rid of just the right amount of carbon in pig iron? The answer was found by an inventor called Henry Bessemer, who was hired by the British government to try to make cheap steel for use in guns. Bessemer's great innovation was to suggest that, once you've got your molten-hot pig iron, you blow air — a lot of air, between 85,000 and 550,000 litres per minute — up from beneath it.

This results in the iron undergoing oxidation, both increasing the temperature of your molten steel and reacting with the impurities. The impurities form a scum at the top of the furnace called slag. This is a mix of metal oxides and other unwanted byproducts such as silicon dioxide, which then needs to be removed, decarbonising the pig iron into the exact ratio you need for steel. With the steel already molten, it can then be poured out into whatever shape you need.

Bessemer became one of the leading figures of the "Second Industrial Revolution" at the tail end of the nineteenth century. He was knighted by Queen Victoria; his steelworks in Sheffield led to it becoming synonymous with steel; and in the US, eight towns were named after him. Without Bessemer, the world would never have known steel's true potential, and our skylines wouldn't be dominated by modern structures that rely on them, such as skyscrapers, railroad tracks and suspension bridges.

Except there's a big problem. "The story you've been told about metallurgy is from a western viewpoint," explains Gill Juleff, an archaeologist from the University of Exeter, and the reason I've come out to Sri Lanka. "It comes from colonialism, and the dominance of Europe. In Asia, there were technologies that were making very good-quality steel. The makers of iron understood it. All of the evidence suggests that India was very familiar with it. They were producing hardened chisels that carved granite even in the Iron Age. You can only do that with steel."

As early as 500 BCE, steel began to originate from the Indian subcontinent that was far greater in quality than any other. The blades were forged with intricate, elaborate patterns and banding, like the marbling of the finest cut of steak. These were harder than any other blades, cut sharper and cost more.

Arabian, Greek, Roman and Chinese writers all described this wonder-material, which became so legendary that a Persian euphemism for cutting someone with a sword was an "Indian answer." It was known as Wootz steel. Just like pepper or other commodities from southern India that moved west along the Silk Road, the steel's rarity made it a luxury item.

"It's not a material that your everyday blacksmith would necessarily want," Juleff says. "High-carbon steel is an awful lot harder to work. It's not for arrowheads or kitchen knives. It became used by specialist swordsmiths." Then, around 1100 CE, the mysterious, intricately patterned blades simply vanished. Subsequent versions emerged (the most famous is Damascus steel), but Wootz steel had disappeared completely. It left a gaping hole in the history of chemistry.

No one could figure out how the Sri Lankans produced steel of such fine quality, and with such intricate patterning, well over a thousand years before it should have been possible. That is, until Juleff discovered the answer. She realised that archaeologists had been looking at the question based on how Europeans worked with iron.

"We discovered that the furnaces were all placed at the top of hills," Juleff explains. "Hundreds of them, of a type we'd never seen before; we only knew they were furnaces because there was slag everywhere. For some reason, the early Sri Lankans had their villages at the bottom of a hill, and then dragged all their iron to the top to smelt it." Initially, the strange furnaces were a puzzle. Typically, a furnace is tall and erect, like a chimney; this creates a natural draught that feeds oxygen to the fire, drawing air in and pushing out the exhaust gases. The Sri Lankan furnaces were totally different. They were flat, half a metre high and 2 metres long, with hundreds of holes bored into the front and back. They looked like oversized harmonicas.

"The answer wasn't immediately obvious why," Juleff says. "And then we realised they were all facing into the wind." What if the Sri Lankans weren't using bellows at all? This is why Juleff asked me to come to Colombo in the off-season. Every year, Sri Lanka is buffeted by two wet seasons: the south-west monsoons from May to September, and the north-west monsoons from December to February. It's a kind of weather you have to experience yourself to truly appreciate.

"A monsoon wind blows up to 90km an hour [56 mph]," says Juleff. "When you're at the top of a hill, you get an aerodynamic effect, where all the wind's rushing up and cresting. You're battered by it. Everyone told me you couldn't run a furnace just using the wind, because it's not strong or reliable enough. So, I decided to experiment. I built one." Juleff's furnace was identical to the Sri Lankan ruins she had found. She fed it using charcoal and iron sourced locally from surface deposits — exactly as would have been available to the villagers who built them.

Then, she waited for the monsoon. "So, we ran this furnace," Juleff says. "And, to begin with, I thought it wasn't working. We had this line of fire behind the front wall, and nothing at the back. I thought everything needed to be burning." It looked like the experts had been right: the monsoon winds weren't regular or consistent enough to blow into the furnace's holes to create the temperatures required.

But then Juleff's mood changed. "It was like a Transformers toy, everything rearranged in my mind. I had a eureka moment! It wasn't wrong at all; it was how it was designed to work. The wind was blowing up the hill — it wasn't blowing into the tubes at all, it was blowing over the top of the furnace. It's like an aeroplane wing: by blowing over the furnace, you're creating this incredible pocket of low pressure." The Sri Lankan furnace wasn't a harmonica, with air puffed through it; instead, it was played like a flute.

This is the Bernoulli effect, the same principle that sticks a race car to the road, or keeps water moving through your plumbing. The change in pressure and the smooth, ordered air flow was creating a furnace beyond anything western science had considered possible. The team continued putting in ore and charcoal throughout the day, then allowed things to cool. The next day, they returned to see what they had produced. At the top was a knotted lump of pure iron — a bloom, as expected. "But then below that, stuck to the bottom of our slag, was another layer of metal," Juleff says. "High-carbon steel. The wind did it. We couldn't stop the wind doing it. We had created a furnace that could make the best steel anywhere in the world."

Juleff had solved the mystery of Wootz steel. Not only did we now know how it was made, we understood why the technology hadn't spread around the world: the technology was anchored in the unique geography of Sri Lanka, and the people who visited weren't scholars, but traders who didn't appreciate the small miracle they were witnessing.

"The metal-makers weren't moving," Juleff says. "They were here, sat in the interior of Sri Lanka, season after season, running these incredible furnaces." Why did Wootz steel vanish? In the twelfth century CE, Sri Lanka was invaded by the Pandya dynasty of southern India. It triggered a societal collapse, as Sri Lankans were forced to pay tribute to their conquerors. The most likely explanation is that, during the chaos of the invasion and its messy aftermath, the traders and middlemen who brought the Wootz steel to the coast, and the ships that transported it around the world, had stopped coming.

It wouldn't have occurred, or mattered, to a Sri Lankan metallurgist that their goods were ending up in the hands of kings and emperors in some distant land they'd never heard of; they'd have only seen that they couldn't sell to local traders any more. The villagers stopped making goods that didn't sell, and moved on to other, more profitable, careers.

Excerpted from "The Age of Alchemy: How Early Innovators Shaped Modern Chemistry," Profile Books, 2026.

Your favorite stretchy workout clothes may be much easier to recycle one day, thanks to a new type of elastic yarn that is as strong and stretchy as today's spandex-containing fabrics.

The yarn, described in a July 25 study in the journal ACS Materials Letters, is built entirely from polyethylene, the plastic used in milk jugs and single-use grocery bags. By contrast, most of today's stretchy fabrics blend spandex, a bouncy-but-weak polyurethane fiber, with a tougher fiber like polyester or nylon.

That combination gives clothes their stretch and durability. But because the fibers are chemically different, it's difficult and costly to separate them for recycling, and chemicals used to break down the fabrics are toxic. The result is that almost none of this material is recycled. An estimated 80% of textiles sold in the U.S. contain spandex, and most end up incinerated or in a landfill, study co-author Svetlana Boriskina, a research scientist in the Department of Mechanical Engineering at MIT, said in a statement.

To solve that problem, the MIT team turned to polyethylene, one of the world's most widely recycled plastics. For the yarn's stretchy core, the researchers created a soft, springy version of polyethylene akin to a rubber band. Around that core, they wound a second, stiffer polyethylene fiber, more like a fishing line, coiling it tightly the way a spring or a twisted phone cord is coiled. Because both materials come from the same plastic family, they don't need to be separated before they're recycled.

In laboratory tests, the researchers melted a spool of the yarn and respun it into new yarn 10 separate times. Each time, they tested its strength, and the recycled yarn performed just as well as the original in every case. In head-to-head tests, the new yarn even outperformed commercial spandex-polyester yarn in maximum load, meaning it could bear more force before breaking, according to the study.

The team has already shown that these lightweight polyethylene fibers can be engineered for other perks, too ‪—‬ like cooling, moisture wicking and stain resistance ‪—‬ building on their earlier work spinning polyethylene into wearable fabric. Even buttons, zippers and buckles could eventually be made from compatible plastics, so a whole garment could be melted down and remade without being taken apart first.

The brain preservation paradox — the discovery of well-preserved human brains among otherwise skeletal remains — has puzzled archaeologists and pathologists alike for decades. Now, new research finally provides a scientific explanation for this longstanding mystery.

"We found that brain preservation isn't a rare anomaly, it's a novel chemical pathway," first study author Alexandra Seviour, a doctoral researcher of paleobiology at the University of Oxford, told Live Science in an email about the new work, published June 19 in the Journal of Proteome Research. "Under the right conditions, preservation actually arises from decay itself: the same reactions that degrade tissue can also weld the breakdown products together into something far tougher."

Despite being one of the first tissues to begin decomposing after death, human brains are surprisingly prolific in archaeology: more than 4,400 preserved brains have been discovered among human remains spanning the last 12,000 years, according to earlier work published by Seviour.

Mummification, freezing, and even saponification (where body fat turns into a greasy substance called grave wax) can all preserve soft tissues, sometimes for millennia. Usually, these processes conserve the structures of multiple body parts, including the internal organs and skin. But bizarrely, around one-third of the archaeological brains recovered don't fit this model, and a shrunken mass of protein is the only surviving tissue left among a cluster of bones.

The bulk of these unexplained brains were found in waterlogged, oxygen-poor (hypoxic) ground — anything from riverbeds and lake shores, to flooded caves and sunken shipwrecks. "Water, being nature's solvent, is typically associated with decomposition, not preservation, " Seviour said. "So the surprise is really the selectivity." In other words: Why is it only the brain which survives under these conditions?

Burying mice

Seviour's team hypothesized that this specific burial environment, combined with the brain's unique structure and chemistry, divert the normal decay pathway away from total breakdown — instead stabilizing the brain's proteins via a different chemical sequence. To test this theory, they buried mouse carcasses in four different water and oxygen conditions and evaluated their decay pathways over a period of six months.

"At 24 hours, 72 hours, one week, six weeks, three months, and six months, we dissected the brains and analysed them using high-resolution mass spectrometry to see exactly which proteins were still present and in what state," Seviour explained. "We were looking for which specific peptides survived and which vanished, and what chemical marks were left on the survivors."

Overall, their analysis yielded more than 1.26 million protein decay trajectories, enabling the team to draw patterns about how and when the chemistry diverged under the different conditions. Early analysis showed that the initial steps of decay were fairly similar, but that after a few weeks, oxygen levels became the controlling factor, with more oxygen leading to faster and more widespread decay. Conversely, wet, low-oxygen conditions favored the formation of toughened protein structures, which resisted further decomposition and preserved the remaining brain tissue.

The solution comes down to free radicals — extremely reactive particles with a single, unpaired electron. Abundant oxygen initiates a chain-like free radical chemical sequence in the brain proteins, which quickly degrades the entire protein structure, Seviour said. However, in hypoxic conditions, there is simply not sufficient oxygen for this same cascade to occur; instead, intermediates in the sequence form crosslinks with other neighboring parts of the brain protein, creating tough and insoluble aggregates that resist decay.

Brain tissue is particularly well-adapted to this localized and self-limiting pathway, Seviour added: it's rich in metals that promote free-radical chemistry, packed with membranes where radicals can accumulate, and contains many "redox-active" amino acids that can absorb free radicals to form crosslinks. The physical barrier of the skull also likely plays a part, restricting the exchange of fluid and oxygen compared with the rest of the body, the researchers said.

Richard Evershed, an organic geochemist at the University of Bristol who was not part of the study, was impressed by the team's comprehensive analysis. Evershed believes it would be fascinating to expand this to other proteins found in the archaeological record.

"Comparing more tissues — other organs and muscles — would be really useful to get an idea whether what was happening in the brain was special compared to what was happening elsewhere, and also to resolve questions regarding proteins preserved in other environments in archaeology such as pots or dental calculus," Evershed told Live Science.

But the implications of the work extend beyond archaeology. "For medicine, the more unexpected finding is that the molecular fingerprint of these decay-resistant peptides closely resembles the fingerprint seen in neurodegenerative diseases like Alzheimer's," Seviour said. One interesting future direction will therefore be to explore how far this similarity extends and whether preserved brains could ultimately help scientists understand the progression of these devastating diseases.

See how much you know about the most complex organ in the human body with our brain quiz!

Science word of the day: Covalent

Pronunciation: Coh-VAY'-lent

What it means: In chemistry, a covalent bond occurs when two atoms share a pair of electrons. Electrons zip around atomic nuclei at different energy levels, or "shells." An atom fills its shells with electrons starting from the lowest-energy shell to the highest-energy one, which is called the valence shell. Valence-shell electrons can interact with the valence shells of other atoms. When two atoms get close enough, their valence electrons can feel the pull from both nuclei at once, binding the two atoms together into a stable molecule.

How to use it in a sentence: When atoms share electrons in a covalent bond, they form some of the most stable bonds in chemistry ‪—‬ which is good news, because these bonds are also the basis of most organic molecules and organisms, including you.

Can you crack our science word of the day puzzle, Chain Word?