History of Materials

Materials are - using the phrase of the late Pr. Stephen Sass (a Northwestern Alumnus) - the "Substance of Civilization" (Sass, 1998). Materials comprise every thing (tool, building, vehicle, item, etc.) that exists, has existed, or will exist. These are metals, polymers, wood, composites, glasses, ceramics, semiconductors, and so on. Because materials physically comprise every object that we use, the science and engineering of these materials is, of course, absolutely foundational to almost every aspect of civilization.

Materials are indeed so important to society that we define epochs in history by the materials that facilitated the technologies used in those periods. For example, the stone age began about 3 mya in Eastern Africa. At this time, ancient peoples discovered techniques to form edges and points from natural rock such as flint or chert. The sharp objects, enabled by human processing of natural stone, allowed for new technologies such as stone-tipped weapons and tools (Figure 1.3.1). Mastery of stone processing allowed ancient peoples to take full advantage of the wonderful properties of stone - a material which is strong (resistance to permanent deformation under an applied force) and wear-resistant (the ability to withstand damage upon repeated use) due to its chemical make-up and the structural arrangement of its atoms. The improved performance enabled by stone tools provided those who had them with great advantages in hunting, building, warfare, artistry, and food processing.

Stone tools served humans for millions of years. Millions of years after the development of stone tool (about (5-6 kya), ancient peoples around the world - from present-day Serbia and Iraq to East Asia - developed methods for smelting copper from the mineral malachite. Prior to this, there's evidence of the practice of metallurgy using smelted tin and lead or rare native metals (metals found naturally in their metallic (non-reacted) forms) such as copper, gold, and even meteoric iron. Copper smelting, however, allowed for the extraction of large amounts of copper from relatively abundant mineral sources and accelerated technology development and broad use - it lead to the formation of a real copper "industry". Tools and weapons made from copper were heavier, tougher, and more durable than their counterparts made of stone and wood, and provided great advantages to those that used them. Perhaps more importantly, copper is much easier to work with than stone, which allowed toolmakers and artisans to produce more complex, intricate, and useful designs (Figure 1.3.2). The use of this material in many areas of society played a central role in the rise of civilization.

This story has many iterations. As copper replaced stone in many applications, bronze (an alloy of copper and (e.g.) arsenic or tin) replaced copper because it is stronger and easier to cast. Bronze, in turn, was largely replaced by iron (less because of properties, and more because of accessibility to raw materials), and then steel. Depending on the application, heavy steel has now been replaced by lightweight aluminum or carbon fiber. During each of these transitions, development of new materials both improved performance of old technologies and enabled new technologies. Developments in all classes of materials; glasses, ceramics, polymers, semiconductors, and others have all ushered in new eras in society and new technologies. These days, we have hundreds of thousands of different sorts of engineered materials that have been discovered and developed over the last few thousand years. The majority of them having been developed in the last hundred. These materials are the substance of civilization and are absolutely critical to modern life.

We're now solidly in the information age - or, to maintain the materials-centric naming convention - the silicon age. These days, development of new materials is happening faster than ever before, and many of the materials we use every day have reached maturity only in the last few decades (for high technology like mobile devices) or centuries (for almost everything else). In Exercise 1.3.1, we'll ask you to consider a material that interests you and explore its utility from the perspective of a materials scientist or engineer.

Consider an article (e.g. an item) of interest and try to learn a little bit about it from the perspective of a materials scientists or engineer. You can choose anything that's a solid and part of something that people use. Some possibilities are:

A component of your computer: the screen, the heat sink, the hard drive or solid state drive, the light-emitting part of the screen).
A component of the building (or car or bus or airplane) you're in: the roof, the walls, the cabinets, the floor, the windows, the lights. Something that you're wearing: the soles of your shoes, the fabric of your pants, your glasses frames.
Something that you're interested in: a turbine in a nuclear reactor, a coronary stent, the compostable plastic in your food container, the glass on your stovetop, your lacrosse stick.

Spend about 20-30 minutes researching the article. Write a few paragraphs about it, including information like:

What material(s) is(are) your article made from? Don't just list chemical elements! Carbon is not a material (although diamond is, and so is graphite.)

If your article of interest is made of lots of materials, just narrow it down to one material sub-system. What do you think the purpose of the material is - that is, how does it function in the article? That is - why is the material there?

Perform some simple web-based research and try to learn a bit about the material. When was it first used, and who invented or discovered it? What selection of properties make it useful? Why do people use this material in particular in the article instead of something else?

No need to dig too deep yet, just try to get some basics.

When you submit an answer you'll see my example discussion for the materials in the sensing chamber of a smoke detector.