6. Such quantities of sand

‘Such quantities of sand’ looks at sustainability and considers three features of the global materials system that need fixing: carbon dioxide emissions, world energy supply, and finite material resources. All societies, however diverse, are comprehensively and universally dependent on material artefacts. The scale of global material flows is enormous, and now greater than for all of human history. In a finite world, there are limits and so it is wise, on some timescale, to favour a circular economy of closed systems (repair, re-use, recycle) over open systems (extract, make, use, discard). Whatever else we do, it helps if we reduce the rate of flow of materials through the economy (use less, use longer).

2. Close inspection

‘Close inspection’ explains that at the core of materials science is the understanding of the internal structure of materials. If we don’t understand the internal structure we shall struggle to explain or to predict material behaviour. If we want to alter the behaviour to make better materials, we probably need to re-engineer the architecture inside. This understanding has been made possible with the development of microscopy, beginning in the 17th century with Robert Hooke and Anton van Leeuwenhoek. Development of X-ray diffraction and electron microscopes has provided atomic resolution leading to improved crystallography and lattice theories for 3-dimensional crystals. Two-dimensional crystals such as graphene and 1-dimensional carbon nanotubes are also described.

1. Gold, sand, and string

‘Gold, sand, and string’ considers elements of the Periodic Table from which every material we use is built. It focuses on three materials—gold, sand, and string—that represent the metallic, inorganic, and organic resources on which we draw. The atomic structure of gold, silver, iron, and copper are described along with the important alloys that can be created from them: bronze, brass, and steel. Quartz (silica) and calcite are also important minerals used in glassmaking and cement manufacture, respectively. Cellulose, a polymer made up of a sugar-molecule chain, is the most abundant material in the biosphere. It is at the heart of cotton and the commodity materials of wood and paper.

4. Electric blue

‘Electric blue’ is concerned with electricity that can drive devices and machines to produce light, sound, and movement, and the appearance of materials, which can be transparent, opaque, shiny, and of different colours. The electrical inventions of Thomas Edison and discoveries of Michael Faraday, Werner von Siemens, and Heinrich Hertz were important, but it was the quantum theory of electrons in solids that explained much of the electrical behaviour of materials. It underpins semiconductor technology, and all its pervasive consequences. Conductivity and resistivity of materials, superconductors, and magnetic fields are considered along with computational models that represent processes in virtual materials where many things are happening simultaneously and at many scales.

5. Making stuff and making things

‘Making stuff and making things’ considers the step-by-step processes in the making of glass, silicon, nickel superalloys, strings and textiles, and plastics, and how they are then used in the manufacture of other goods. For pottery, ceramics, bricks, and tiles though, the making of the material and of the artefact are merged into a single act. The chemistry lies in the mineral reactions that transform soft matter into hard in the hot kiln. Material-as device, device-as-material, and material-as-object are also considered along with the valuable applications of osmium and caesium. What does the future of material science hold? Will motile biomaterials ever be realized?

3. Tough but slippery

‘Tough but slippery’ considers the physical characteristics of materials. Understanding properties in certain materials allows us to predict their behaviour and to use them appropriately in industrial processes. Aerospace engineers require lightweight materials with low density, but oil industry drilling engineers use the dense mineral barytes to make heavy muds for controlling the pressures in wells. Thermal expansivity, specific heat, and thermal conductivity are properties that describe the thermal behaviour of materials. Mechanical material properties include stiffness, strength, hardness, weakness, softness, brittleness, and toughness. In metals, yield and plasticity are of the greatest significance and value. Elasticity of polymer molecules and the viscosity and specific energy of liquids and gases are also described.