"Stuff Matters"

I wish a younger me could have read this book by Mark Miodownik and Sarah Scarlett, so that I didn't have to live in ignorance of so many things around me for so long.
__ We may like to think of ourselves as civilized, but that civilization is in large part bestowed by material wealth. Without this stuff, we would quickly be confronted by the same basic struggle for survival that animals are faced with. .. The fundamental importance of materials to us is apparent from the names we have used to categorize the stages of civilization—the Stone Age, Bronze Age, and Iron Age—with each new era of human existence being brought about by a new material.

• Metals are fundamentally different from these other materials because they can be hammered into shape: they flow, they are malleable. Not only that, they get stronger when you hit them;... And you can reverse the process simply by putting metal in a fire and heating it up, which will cause it to get softer.
• metals are made from crystals... Viewed through an electron microscope, the crystals in a piece of metal look like crazy paving, and inside those crystals are squiggly lines—these are dislocations. They are defects in the metal crystals, and represent deviations in the otherwise perfect crystalline arrangement of the atoms— ... This plastic behavior is achieved by the dislocations moving within the crystal. As they move they transfer small bits of the material from one side of the crystal to the other. They do this at the speed of sound. As you bend a paper clip, you are causing approximately 100,000,000,000,000 dislocations to move at a speed of hundreds of meters per second.
• The melting point of a metal is an indicator of how tightly the metal atoms are stuck together and so also affects how easily the dislocations move.
• 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.
• 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.
• (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). There is another problem, too. 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 .... This is a major obstacle because inside a fire there is rather a lot of carbon around.
• an object that epitomized their civilized approach to life: the Roman razor blade. These novacili, and the barbers who wielded them, allowed the Romans to retreat clean-shaven, groomed in order to distinguish themselves from the savage hordes that had driven them out.
• By separating the different types of steel, (the Japanese) 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.
• 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.
• Mushethe 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.
• But with chromium present something different happens. Like some hugely polite guest, it reacts with the oxygen before the host iron atoms can do so, creating chromium oxide. Chromium oxide is a transparent, hard mineral that sticks extremely well to steel. In other words, it doesn’t flake off and you don’t know it is there. Instead it creates an invisible, chemically protective layer over the whole surface of the steel. What’s more, we now know that the protective layer is self-healing;
• Its lack of hardness allowed the alloy to do other things, though, which only became apparent later in the century—namely, it could be formed into complex shapes, leading eventually to one of the most influential pieces of sculpture, present in almost every house: the kitchen sink. Stainless steel sinks are indomitable
• Brearley did manage to create cutlery from stainless steel, and it’s the transparent protective layer of chromium oxide that makes the spoon tasteless, since your tongue never actually touches the metal and your saliva cannot react with it; it has meant that we are one of the first generations who have not had to taste our cutlery.
• Hephaistos, the Greek god of metals, fire, and volcanoes, whose classical image is that of a smith at a forge. Physically handicapped, he is misshapen, suffering probably from arsenicosis, an infliction common to smiths of the time, who were exposed to high levels of arsenic poisoning during the smelting of bronze, which resulted in lameness and skin cancers.

Paper:

• tree’s core strength derives from a microscopically small fiber called cellulose, which is bound together by an organic glue called lignin. This is an extremely hard and resilient composite structure that can last hundreds of years. Extracting the fibers of cellulose from the lignin is not easy. It is like trying to remove chewing gum from hair. Delignification of wood, as the process is called, involves crunching up the wood into tiny pieces and boiling them at high temperatures and pressures with a chemical cocktail that breaks down the bonds within the lignin and frees up the cellulose fibers.
• Paper yellows with age for two reasons. If it is made from cheap, low-grade mechanical pulp, it will still contain some lignin. Lignin reacts with oxygen in the presence of light to create chromophores (meaning, literally, “color-carriers”), which turn the paper yellow as they increase in concentration.
• Large numbers of books from the nineteenth and twentieth centuries were printed on this so-called acid paper and can now be easily identified in book shops and libraries by their bright yellow appearance.
• Reversing the process in the darkroom by shining light through the film onto the photographic paper transformed the silver bromide and chloride molecules into little crystals of silver metal, which appear as specks of gray on the paper... To prevent this, the photo was “fixed” with a chemical that washed away the unreacted silver halides from the paper.
• but it wasn’t until the Romans replaced the scroll with the codex—or, as we call it now, the book—that the material reached its full potential... The genius of this so-called codex format—a stack of papers bound to a single spine and sandwiched between covers—and the reason why it usurped the scroll, is that it allows for text on both sides of the paper and yet still provides a continuous reading experience.
• The reason for this is that printing on thermal paper does not mean adding ink to it. Rather, the ink is already encapsulated within the paper, in the form of a so-called leuco dye and an acid. The act of printing requires only a spark to heat up the paper so that the acid and dye react with each other, converting the dye from a transparent state into a dark pigment. It is this cunning paper technology that ensures that cash registers never run out of ink. But over time the pigment reverts to its transparent state and so the ink fades,
• This stiffness is controlled by the addition of “sizings,”—fine powder additives, such as kaolin and calcium carbonate, that among other things reduce the paper’s ability to absorb moisture, causing inks to dry on its surface rather than infuse its fibers, while also allowing the whiteness of the paper to be controlled.
• there is an easy chemical test that can confirm whether it’s cotton or not. This is done in many shops using an iodine pen. When used on cellulose-based paper, the iodine reacts with the starch in the cellulose to create a pigment and so appears black. When the same pen is used on cotton paper there is no starch for the iodine to react with, and no mark appears.
• watermarking. This is a pattern or picture that is embedded in the paper but can only be seen when light is transmitted through the paper—in other words, when you hold the banknote up to the light. Despite the name, this is not a water stain or an ink of any sort. It is engineered by creating small changes in the density of the cotton, so that different parts of the note look lighter and darker to produce a pattern
• Because the Janus particles are physical ink and need to physically rotate when the text is changed, they cannot be switched as rapidly as the liquid crystal display of an iPad or smartphone, and so at the moment they are unable to show movies

Concrete:

• When concrete sets, it is reacting with the water, initiating a chain of chemical reactions to form a complex microstructure deep within the material, so that this material, despite having a lot of water locked up inside it, is not just dry but waterproof.
• The trick is to heat them to a temperature of about 1450°C. This is a temperature far exceeding that of an average wood or coal fire, which is between 600 and 800°C if it is glowing red or yellow hot. At 1450°C a fire will glow white hot, with no tinge of red or even yellow in the flames but instead a hint of blue. It is so bright it is unnerving and almost painful to look at. At these temperatures, rock starts to fall apart and re-form to create a family of compounds called calcium silicates.
• In the case of cement, the skeleton is made up of calcium silicate hydrate fibrils, which are crystal-like entities that grow from the calcium and silicate molecules, now dissolved in the water, in a way that appears almost organic
• This volcanic ash resulted from the super-heating of silicate rock, which was then spewed out of a volcanic vent—a process suspiciously similar to that of making modern cement. All the Romans had to do was put up with the smell and mine the rock powder that had been accumulating for millions of years. This naturally made cement
• The most impressive piece of Roman concrete engineering, however, is in its capital: the dome of the Pantheon in Rome. Still standing today, it is two thousand years old but still the largest unreinforced concrete dome in the world.
• There are two ways of breaking a material. One is to break it plastically, which is what happens when, for example, you pull a piece of chewing gum apart:... The other way of breaking a material is to create a crack through it, which is how a glass or a tea cup breaks:
• The Romans never solved this problem and so only used concrete in situations where it was being compressed rather than stretched, such as in a column, dome,
• Joseph’s solution was to embed loops of steel inside the concrete. He couldn’t have known that cement bonds very well to steel... But, as luck would have it, steel and concrete have almost identical coefficients of expansion.
• This type of attrition and erosion is what all stone buildings have to put up with. It is also what mountains have to put up with, which is how they get eroded. To prevent stone or concrete structures being similarly afflicted, maintenance of their fabric needs to be carried out every fifty years or so.
• And it was discovered that one particular type called B. pasteurii could excrete the mineral calcite, a constituent of concrete. These bacteria were also found to be extremely tough and able to survive dormant, encased in rock, for decades. Self-healing concrete has these bacteria embedded inside it along with a form of starch, which acts as food for the bacteria.

Cocoa:

• But cocoa butter is a special fat for many reasons. For one, it melts at body temperature, meaning that it can be stored as a solid but becomes a liquid when it comes into contact with the human body. This makes it ideal for lotions. Moreover, it contains natural antioxidants, which prevent rancidity, so it can be stored for years without going off
• Cocoa fat has another trick up its sleeve: it forms crystals, and these are what give chocolate bars their mechanical strength.
• Type V is an extremely dense fat crystal. It gives the chocolate a hard, glossy surface with an almost mirror-like finish,.. They have to be created through a process called tempering, in which preformed “seed” Type V crystals are added during the final process of solidification. These give the slower-growing Type V crystals a head start over the faster-growing Type III and IV crystals,
• What happens next is that the ingredients of the chocolate, once bound together by the rigid cocoa butter matrix, are now free to flow to your taste buds.
• As with all chemical reactions there are a vast number of different variables that affect this outcome: the ratio of the ingredients, the surrounding temperature, the availability of oxygen, and many others. This means that the taste of chocolate is highly dependent not just on the ripeness and species of the cocoa bean, but also on how high the rotting piles of beans are stacked, how long they are left to rot, and generally what the weather is like.
• What you get for your money, though, is not just the delicate fruity flavors from the fermented esters, but a set of earthy, nutty, almost meaty flavors. These are produced in the process that comes after fermentation, when the beans are dried and roasted.
• Only in this case the caramelizing reaction takes place inside the cocoa bean, turning it from white to brown and creating a wonderful range of nutty caramel flavor molecules.
• also contributes to the color and flavor of the cocoa: the Maillard reaction. This is when a sugar reacts with a protein... When subjected to temperatures of 160°C and above, these proteins and carbohydrates start to undergo Maillard reactions, reacting with the acids and esters (produced by the earlier fermentation process) and resulting in a huge range of smaller flavor molecules.
• Then came a moment of counterintuitive genius: having removed and purified the cocoa fat, and having pulverized the cocoa powder separately, why not mix them back together again, adding in some sugar, to create an ideal cocoa bean
• These days the type of milk added to chocolate varies widely throughout the world, and this is the main reason that milk chocolate tastes different from country to country. In the USA the milk used has had some of its fat removed by enzymes, giving the chocolate a cheesy, almost rancid flavor. In the UK sugar is added to liquid milk, and it is this solution, reduced to a concentrate, that is added to the chocolate, creating a milder caramel flavor. In Europe powdered milk is still used, giving the chocolate a fresh dairy flavor with a powdery texture.