Materials Science
Before the modern era, materials were developed by artists and crafts people, artisans, alchemists and dabblers largely through trial and error. The technical sophistication that can be achieved this way is impressive, as a visit to the British Museum amply illustrates.
Materials science is a fundametally different approach: it is the use and development of theory (physics, chemistry, biology) to understand and develop new materials. Although Materials Science is a fundamentally multidisciplinary approach, one aspect of the subject unites everyone, the link between structure and materials properties. Whether it is macro-structure, micro-structure, nano-structure or atomic-structure: size matters, with each different structural scale presenting its owns challenges. By understanding structure at the right scale and you can control the corresponding properties such as colour, strength, smoothness, magnetism etc... Material scientists all spend a lot of time trying to observe, control and manipulate structure.
This approach is largely a 20th century innovation, and had yielded more new materials in 100 years than were developed in all previous history. There are hundreds of new materials produced every year. Some are exciting developments of familiar materials, such as new aluminium alloys for the car industry, and some seem miraculous such as silicon chips, glass that cleans itself, polymers that self-heal, transparent concrete, and digital paper.
The structures of living organisms represent the pinacle of such multi-scale control, which is why materials scientists spend a lot of time talking to biologists and biochemists. Many of the most exciting developments of materials science in the 21st century are likely to be in the overlap between evolutionary computing, biology and materials science