Class 6 Science

Sorting Materials into Groups

  • All things are made of one or more materials.
  • Same things can be made from different types of materials.
  • It may be man-made or naturally occurring.
  • Materials occupy space.
  • Materials have mass.
  • Materials can be classified on the basis of many criteria.
  • Materials can be classified on the basis of physical state; as solid, liquid and gas.

Solid Liquid & Gas

solid liquid and gas
Fig:States of Matter

Solid: Solid has definite shape and definite volume. Examples: Stones, wood, plastic, common salt, steel, ice, glass, etc.

Liquid: Liquid has indefinite shape but definite volume. Examples: Water, milk, oil, etc.

Gas: Gas has indefinite shape and indefinite volume. Examples: Oxygen, nitrogen, carbon dioxide, etc.

Other Criteria For Sorting Materials:

Appearance: Different materials look different from each other. The appearance depends on colour, hardness, texture, and lustre.

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:

Soluble: Material which easily dissolves in water is called soluble, e.g. salt, sugar, alum, etc.

Insoluble: Material which does not dissolve in water is called insoluble, e.g. sand, chalk, iron, etc.

Note: Since water is considered as universal solvent, so solubility in water is taken as standard in most of the definitions; related to solubility.

Transparent: The material which allows light to pass through it is called transparent, e.g. acrylic sheet, glass, water, air, etc.

transparent translucent opaque

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.

Sorting Materials: NCERT Solution

Sorting Materials: MCQ Quiz