Classification of materials:
On the basis of their physical properties, the materials can be classified into following four types.
Elastic Material: When we apply some external forces on a body, it undergoes deformation. If the material regain its shape on the removal of forces, it is known as elastic material. e.g. Steel, Rubber etc.
Plastic Material: If the material does not regain its original shape on removal of external forces then it is known as plastic material. e.g. lead
Ductile Material: The ability of a material to be drawn into wires is known as ductility of a material. e.g. gold, silver etc.
Brittle Material: When we apply some external force on a material, it does not undergo deformation. It fails by rupture. e.g. glass