[1] In selecting a material, the primary concern of engineers is to match the material properties to the service requirements of the component. Knowing the conditions of load and environment under which the component must operate, engineers must then select an appropriate material, using tabulated test date as the primary guide. They must know what properties they want to consider, how these are determined, and what restrictions or limitations should be placed on their application.

[2] One means of distinguishing one material from another is by comparison of physical properties. These include such characterison as density (weight); melting point; optical properties (such as transparency, opaquencess, or color); the thermal properties of specific heat, coefficient of thermal expansion, and thermal conductivity; electrical conductivity; and magnetic properties. In some cases, the physical properties may be of prime importance when one is selecting a material.

[3] Mechanical properties are those responses a material has to the