WHAT MAKES BASIS OF SORTING MATERIALS INTO GROUPS
Materials can be classified on the basis of physical state; as solid, liquid and gas.
The other basis of sorting of materials could be based on the following criteria's
Appearance: Different materials look different from each other. The appearance depends on color, hardness, texture, and luster.
Hardness: hardness is another property of materials. Some materials are very hard while some are very soft.
Hard- Material which are difficult to compress are called hard, e.g. diamond, stone, wood, steel, etc. Diamond is the hardest natural substance.
Soft- Materials which can be compressed easily are called soft, e.g. chalk, cotton, rubber, etc.
Solubility or insolubility:
Insoluble: Material which does not dissolve in water is called insoluble, e.g. sand, chalk, iron, etc
Transparency- The material which allows light to pass through it is called transparent, e.g. acrylic sheet, glass, water, air, etc.
Opaque- The material which does not allow light to pass through it is called opaque, e.g. wood, iron, asbestos, etc.
Translucent: The material through which light can pass partially is called translucent, e.g. butter paper, thin curtain, etc.
Metals: Materials which are hard, have such luster and are good conductors of heat and electricity are called metals, e.g. iron, copper, gold, etc.
Non-metal: Materials which are brittle, which don’t have luster and are bad conductors of heat and electricity are called non-metals, e.g. coal, chalk, rubber, soil, etc.