An Exploration of Materials Science

The development of mankind is defined in terms of advances in materials: the Stone Age, the Bronze Age, and the Iron Age. The dramatic advances in architecture and building introduced by the Roman Empire were possible only because of the invention of a new material - concrete. The Industrial Revolution was to a large extend made possible by advances in the sue of materials in industrial equipment, as was the rapid development of the railroads in the late nineteenth century, and the skyscrapers that began to define the skylines of American cities in the early twentieth century.

In the last half century, the growth of materials technology has been explosive, and its impact on our daily lives, pervasive. Beginning with the invention of the transistor in the 50's, the electronics revolution, enabled by advances in materials, has dramatically and irreversibly changed our lives. Some of us remember the sage career advice given to Dustin Hoffman in the 1960's film The Graduate - "Plastics". The use of plastics is now so widespread that it is difficult to imagine life without them The double edged sword inherent in the use of new technologies is apparent in today's concern with the disposal of non biodegradable plastics.

If The Graduate were to be remade today, the career advice might well be - "Ceramics". While ceramics were the first Engineering Materials, finding application as building materials and pottery in the Stone Age, recent technological advances combined with their unique electrical properties, hardness, durability and heat resistance are making ceramics the material of the future. One of the most recent Nobel Prizes for Physics was awarded to Bednorz and Mueller of IBM for the discovery that certain complex ceramic materials will conduct electricity without resistive loss at temperatures substantially higher than those for conventional metallic superconductors. Artificial diamond is on the verge of having major impacts on fields as diverse as optics, wear coatings, and substrates for electronic circuits. In the near future we can expect to find major advances in the use of ceramics in applications as diverse as microelectronics, superconductors, automotive and aircraft engines, prosthetic implants, and chemical process equipment.

Today's fundamental research activities in the Universities and Research Laboratories give us confidence that we have not seen the end, but rather only the beginning, of advances in Materials Science and Technology that will profoundly effect the way we live our lives. We can expect to see biodegradable plastics produced by genetically engineered microbes, structural materials that are analogs of naturally occurring materials such as shell or bone, improved bioengineered materials to replace joints, bone tendons and skin, super hard materials with hardness greater than that of diamond, aircraft skins that can detect and respond to changes in ambient conditions or to structural damage, bridges made of strong, light weight fiber reinforced plastic composites, and road surfaces that will last for a human lifetime. We have just begun to see the impact of The Materials Revolution. We have chosen Materials Science as the subject of this teaching module both because of its importance and pervasiveness in our lives, and because it brings together all of the major physical science disciplines and applies them to practical problems with which the student can identify. We have tried to bring in elements of chemistry, physics, mathematics, engineering and the use of computers. We have incorporated materials that represent all of the major classes of materials: metals, ceramics and plastics.

The core of the module is the laboratory work. Here we have tried to keep things as "hands on" as possible. The intent is for the students to get an acquaintance with the scientific method, with laboratory practice, with physical observation and data taking and analysis, and to get a feeling for the fundamental differences between the various classes of materials.

Materials science involves the preparation and characterization of materials to ensure that they have the properties required for a particular application. Classes of materials include plastics, glass, ceramics, metals, and semiconductors. Key properties of materials include their mechanical behavior, electrical, magnetic optical and thermal characteristics, chemical stability and other physical properties such as density and grain structure.

In this teaching module, students will be introduced to the preparation and characterization of a metal (tin), a plastic (polyester), and a ceramic (anchor (very fine) cement). They will first prepare the samples by either heating and melting the raw material, in the case of tin, or by a chemical curing process for the polyester resin and anchor cement. After the preparation of the test samples, the students will examine their optical and physical characteristics, determine their relative electrical and thermal properties and investigate their mechanical behavior and chemical stability.

The photos below were taken at the Explorations in Materials Science workshop presented at the 1999 San Diego Science Educators Association Meeting.