Stuff Matters: Exploring the Marvelous Materials That Shape Our Man-Made World

by Mark Miodownik

The samurai innovation was to be able to distinguish high-carbon steel, which is hard but brittle, from low-carbon steel, which is tough but relatively soft. They did this purely by how it looked, how it felt in their hands, and how it sounded when struck. By separating the different types of steel, they could make sure that the low-carbon steel was used to make the center of the sword. This gave the sword an enormous toughness, almost a chewiness, meaning that the blades were unlikely to snap in combat. On the edge of the blades they welded the high-carbon steel, which was brittle but extremely hard and could therefore be made very sharp. By using the sharp high-carbon steel as a wrapper on top of the tough low-carbon steel they achieved what many thought impossible: a sword that could survive impact with other swords and armor while remaining sharp enough to slice a man’s head off. The best of both worlds.

As with any chemical reaction, if you get the ratio of the ingredients wrong, then you get a mess. In the case of concrete, if you add too much water there won’t be enough calcium silicate from the cement powder to react with, and so water will be left over within the structure, which makes it weak. Similarly, if you add too little water there will be unreacted cement left over, which again weakens the structure. It is usually human error of this sort that proves the undoing of concrete. Such poor concrete can go undiscovered but then lead to catastrophe many years after the builders have departed. The extent of the devastation due to the 2010 earthquake in Haiti was blamed on shoddy construction and poor-quality concrete: an estimated 250,000 buildings collapsed, killing more than 300,000 people, and making a million more homeless. What is worse is that Haiti is by no means unusual. Such concrete time bombs are scattered throughout the world.

In a world where we have industrialized so many materials, including those we used to hold sacred, such as gold and diamond, I like to think there may again be a place for a material valued solely for its beauty and significance. Most people will never hold a piece of aerogel in their hand, but those who do never forget it. It is a unique experience. There is no weight to it that you can perceive, and its edges fade away so imperceptibly that it is impossible to see where the material stops and the air begins. Add to this its ghostly blue color and it really is like holding a piece of sky in your hand. Aerogels seem to have the ability to compel you to search your brain for some excuse to be involved with them. Like an enigmatic party guest, you just want to be near them, even if you can’t think of anything to say. These materials deserve a different future, not of oblivion or embedment in a particle accelerator, but to be valued for themselves.

It is often said that there are very few places left on Earth that have yet to be discovered. But those who say this are usually referring to the places that exist at the human scale. Take a magnifying glass to any part of your house and you will find a whole new world to explore. Use a powerful microscope and you will find another, complete with a zoo of living organisms of the most fantastic nature. Alternatively, use a telescope and a whole universe of possibilities will open up before you. Ants build cities at their scale, and bacteria build cities at their scale. There is nothing special about our scale, about our cities, about our civilization, except that we have a material that allows us to transcend our scale—that material is glass.

“It is important to note,” he said, “that although diamond is culturally revered as the superior form of carbon, it is in fact incapable of deep expression, and unlike graphite no good art can come from diamond.”

But diamonds are not forever, at least on the surface of this planet. It is, in fact, diamond’s sibling structure, graphite, that is the more stable form, and so all diamonds, including the Great Star of Africa in the Tower of London, are actually turning slowly into graphite.