Materials are probably more deep-seated in our culture than most of us realize.Transportation, housing, clothing, communication, recreation, and food production—virtually every segment of our everyday lives is influenced to one degree or anotherby materials.Historically, the development and advancement of societies have been intimately tied to the members’ ability to produce and manipulate materials to fill their needs. In fact, early civilizations have been designated by the level of their materials development (Stone Age, Bronze Age, Iron Age).


The earliest humans had access to only a very limited number of materials, those that occur naturally: stone, wood, clay, skins, and so on.With time they dis- covered techniques for producing materials that had properties superior to those of the natural ones; these new materials included pottery and various metals. Fur- thermore, it was discovered that the properties of a material could be altered by heat treatments and by the addition of other substances.At this point,materials uti- lization was totally a selection process that involved deciding from a given, rather limited set of materials the one best suited for an application by virtue of its char- acteristics. It was not until relatively recent times that scientists came to understand the relationships between the structural elements of materials and their properties.
This knowledge, acquired over approximately the past 100 years, has empowered
them to fashion, to a large degree, the characteristics of materials.Thus, tens of thousands of different materials have evolved with rather specialized characteristics that meet the needs of our modern and complex society; these include metals, plastics, glasses, and fibers.


The development of many technologies that make our existence so comfortable has been intimately associated with the accessibility of suitable materials. An advancement in the understanding of a material type is often the forerunner to the stepwise progression of a technology. For example, automobiles would not have been possible without the availability of inexpensive steel or some other comparable substitute. In our contemporary era, sophisticated electronic devices rely on components that are made from what are called semicon-
ducting materials.



The approximate dates for the beginnings of Stone, Bronze, and Iron Ages were 2.5 million
BC, 3500 BC and 1000 BC, respectively.