What is metal?
Metals have a common set of properties that make them most useful among the engineering materials. A metal may be described as a material which is solid at room temperature, has relatively high density high melting temperature, low specific heat, good electrical and thermal conductivity, strength and hardness etc. Most metals are elastic to a limit. They deform in proportion to stress and return to the original state when the stress is released at higher stresses they defom plastically Some metals will accept a deal of plastic deformation before failure. Metals play an important role in the industries of a nation. Thus it is essential for an engineer to know about the sources and techniques of its production. A metal can exist in the solid, liquid or gaseous state depending upon the temperature and pressure exerted on the metal. Some of the common metals and alloys are iron, copper, aluminium, nickel, tin, brass and bronze, etc.
What is Non-Metal?
The non-metals in the solid state are mostly brittle and are poor electrical and thermal conductors. They do not form alloy but combined chemically to form compound. Some of the non-metals are glass, wood, plastics and concrete etc. Hence in accordance to their properties the materials are broadly divided into two groups ie, Metals and Non-Metals.