We often don’t think about what role materials play in our lives until something goes wrong--we leave something near the stove and it melts, a plastic part breaks in the cold, etc.   This website presents just the mere basics of the vast world of material science.  Thousands of years ago the materials we built things out of consisted of  stones, sticks, bones and animal hides.  Today we mine and process raw materials to make them more useful and cost effective.  We have hundreds of kinds of steel and plastics with different properties and advantages. Engineers need to be educated about material science in order to decide what materials should be used in their product or structure.  Materials are tested by engineers so that we know what stresses they can withhold and at what expense to pocketbooks and to the environment.   Even in things we think of as simple--furniture, wallpaper, hammers, nails--a great deal of thought and testing goes into material selection. Nothing is simple, and as problem solvers engineers study materials with one primary goal in mind:  to maximize the advantages of a material while minimizing the disadvantages.  On the following pages you will learn how materials are categorized and what types of properties materials have.