Stuff Matters

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Highlights

After all, everything is made from something, and those who make things—artists, designers, cooks, engineers, furniture makers, jewelers, surgeons, and so on—all have a different understanding of the practical, emotional, and sensual aspect of their materials. — location: 119

The central idea behind materials science is that changes at these invisibly small scales impact a material’s behavior at the human scale. — location: 132

But there is also a scientific discipline especially dedicated to systematically investigating our sensual interactions with materials. This discipline, called psychophysics, has made some very interesting discoveries. — location: 145

For instance, studies of “crispness” have shown that the sound created by certain foods is as important to our enjoyment of them as their taste. This has inspired some chefs to create dishes with added sound effects. — location: 146

Some potato chip manufacturers, meanwhile, have increased not just the crunchiness of their chips but the noisiness of the chip bag itself. I explore the psychophysical aspects of materials in a chapter on chocolate and show that it has been a major driver of innovation for centuries. — location: 148

Radivoke Lajic, who lives in northern Bosnia, is a man who knows all about strange bits of metal falling from the sky. Between 2007 and 2008 his house was hit by no fewer than five meteorites, which is statistically so hugely unlikely that his claim that aliens were targeting him seems almost reasonable. — location: 185

At some point humans made the discovery that would end the Stone Age and open the door to a seemingly unlimited supply of the stuff. They discovered that a certain greenish rock, when put into a very hot fire and surrounded by red-hot embers, turns into a shiny piece of metal. This greenish rock was malachite, and the metal was, of course, copper. It must have been the most dazzling revelation. Suddenly the discoverers were surrounded not by dead inert rock but by mysterious stuff that had an inner life. — location: 232

The pyramids of Egypt are an example of what became possible once there were plentiful copper tools. Each block of stone in each pyramid was extracted from a mine and individually hand-carved using copper chisels. It is estimated that ten thousand tons of copper ore were mined throughout ancient Egypt to create the three hundred thousand chisels needed. — location: 243

Gold is another relatively soft metal, so much so that rings are very rarely made from pure gold metal because they quickly scratch. But if you alloy gold, by adding a small percentage of other metals such as silver or copper, you not only change the color of the gold—silver making the gold whiter, and copper making the gold redder—you make the gold harder, much harder. — location: 249

In the case of gold alloys, you might wonder where the silver atoms go. The answer is that they sit inside the gold crystal structure, taking the place of a gold atom, and it is this atom substitution inside the crystal lattice of the gold that makes it stronger. — location: 253

Alloy design is thus the art of preventing the movement of dislocations. — location: 258

These atom substitutions happen naturally inside other crystals too. A crystal of aluminum oxide is colorless if pure but becomes blue when it contains impurities of iron atoms: it is the gemstone called sapphire. — location: 259

aluminum oxide crystal containing impurities of chromium is the gem called ruby. — location: 260

The ages of civilization, from the Copper Age to the Bronze Age to the Iron Age, represent a succession of stronger and stronger alloys. — location: 261

Bronze is an alloy of copper, containing small amounts of tin or sometimes arsenic, and is much stronger than copper. — location: 262

The only problem is that tin and arsenic are extremely rare. Elaborate trade routes evolved in the Bronze Age to bring tin from places such as Cornwall and Afghanistan to the centers of civilization in the Middle East for precisely this reason. — location: 264

Steel, the alloy of iron and carbon, is even stronger than bronze, with ingredients that are much more plentiful: pretty much every bit of rock has some iron in it, and carbon is present in the fuel of any fire. Our ancestors didn’t realize that steel was an alloy—that carbon, in the form of charcoal, was not just — location: 269

a fuel to be used for heating and reshaping iron but could also get inside the iron crystals in the process. — location: 271

Carbon doesn’t do this to copper during smelting, nor to tin or bronze, but it does to iron. — location: 272

(the carbon in steel doesn’t take the place of an iron atom in the crystal, but is able to squeeze in between the iron atoms, creating a stretched crystal). — location: 274

If iron becomes alloyed with too much carbon—if, for instance, it contains 4 percent carbon instead of 1 percent carbon—then it becomes extremely brittle and essentially useless for tools and weapons. — location: 275

The mystique that surrounded steelmaking engendered various myths, and the unification and restoration of order to Britain in the wake of the Roman retreat was symbolized by one of the most enduring of these: Excalibur, the legendary sword of King Arthur, sometimes attributed with magical powers and associated with the rightful sovereignty of Britain. — location: 296

This was nowhere more true than in Japan, where the forging of a samurai blade took weeks and was part of a religious ceremony. The Ama-no-Murakumo-no-Tsurugi (“Sword of the Gathering Clouds of Heaven”) is a legendary Japanese sword which allowed the great warrior Yamato Takeru to control the wind and defeat all his enemies. — location: 301

These samurai swords were made from a special type of steel called tamahagane, which translates as “jewel steel,” made from the volcanic black sand of the Pacific (this consists mostly of an iron ore called magnetite, the original material for the needle of compasses). — location: 306

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. — location: 314

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. — location: 316

One day a Sheffield-based engineer named Henry Bessemer stood up at a meeting of the British Association for the Advancement of Science and announced he had done it. His process didn’t require the elaborate procedures of the samurai. He could create tons of liquid steel. It was a revolution in the making. The Bessemer process was ingeniously simple. It involved blowing air through the molten iron, so that the oxygen in the air would react with the carbon in the iron and remove it as carbon dioxide gas. It required a knowledge of chemistry that for the first time put steelmaking on a scientific footing. Moreover, the reaction between the oxygen and the carbon was extremely violent and gave off a lot of heat. This heat raised the temperature of the steel, keeping it hot and liquid. The process was straightforward and could be used on an industrial scale; it was the answer. The only problem with the Bessemer process was that it didn’t work. Or at least that was what everyone who tried it said. Soon, angry steelmakers, who had bought the license from Bessemer and invested large sums of money in equipment only to produce brittle iron, started asking for their money back. He had no answers for them. He didn’t really understand why the process was successful sometimes and unsuccessful at others, but he continued to work on his technology, and with the help of the British metallurgist Robert Forester Mushet he adapted his technique. Rather than trying to remove the carbon until just the right amount was left, about 1 percent, Mushet suggested removing all the carbon and then adding 1 percent carbon back in. This worked and was repeatable. Of course, when Bessemer tried to interest the world in this new process, the other steelmakers ignored him, assuming that it was yet another swindle. They insisted that it was impossible to create steel from liquid iron, and that Bessemer was a con artist. In the end he saw no option but to set up his own steel works and just start making the stuff himself. After a few years the firm of Henry Bessemer & Co. was manufacturing steel so much more cheaply and in such larger quantities than his rival firms that they were eventually forced to license his process, in the end making him extremely rich and ushering in the machine age. — location: 327