Revision Notes of Ch 4 Sorting Materials into Groups Class 6th Science

Topics in the chapter

  • Object around us
  • Properties of material
  • Appearance 
  • Solubility in water
  • Solute, solvent and solution
  • How are material grouped
  • What is shorting?
  • Grouping on the basis of similarity and differences 
  • Advantage of classification

Object Around Us

→ Objects are made up of one or more materials.

→ One material can be used to make different type of objects.

→ It may be man-made or naturally occurring.

→ Material is a substance which is used to make different objects.

Properties of materials

→ Material occupy space.

→ Materials have mass.

• Material can be classified on the basis of physical state as:
(i) Solid
Examples:  sand, steel and stone.

(ii) Liquid
Examples:  oil, water and milk.

(iii) Gas
Examples: steam, nitrogen and oxygen.

General properties of material


→ Lustrous (all metals are lustrous, some are more and some are less).

→ Non-lustrous (wood, rubber and piece of rock)

Hardness (Hard and soft)

→ Brittle (break into small pieces or become powdered when hammered. Eg: - glass and salt)

→ Malleable (spread into sheets when beaten. Metal are malleable

→ Ductile ( which can draw into thin and long wire)


→ Transparent (Materials that allow the entire light pass through it, like glass, water etc.)

→ Translucent (Materials that allow some light to pass through it, like coloured glass, oiled paper.)

→ Opaque (The material which do not allow light to pass through it, like stone, wood etc.)


→ Good conductor (Metals are good conductor ; electricity can pass through it)

→ Bad conductor (non-metals ; electricity can’t pass through it)


→ Good conductor (metals are good conductor)

→ Bad conductor (non-metals are bad conductor)

Materials may float and can sink in water

→ Material which sinks in water is denser than water

→ Material which floats on water is less dense than water.

Solubility of a substance in water

→ The substance like salt and sugar which disappear in water are called as soluble.

→ The substances which don’t disappear in water are known as insoluble in water.

Miscible and immiscible liquid

→ When two liquid mixed and they do not mixed well is known as immiscible.

→ The liquids which mix well with water are said to be miscible.

Solute, solvent and solution?

→ The substances which dissolve in water are called solute.

→ A solvent is a substance that dissolves the solute to make the solution.

→ The mixture of solute and solvent is called solution.

How are material grouped

• The materials which are similar in one or two ways can be put in one group.

→ Things made from wood.

→ Things made from fibre.

→ Things made from metal.

→ Things made from ceramic.

→ Things made from glass.

→ Things made from plastic.

→ Things made from rubber.

→ Things that are liquids such as oil.

Advantages of classification

→ Helps in identifications of objects.

→ Helps in sorting of objects.

→ Helps in locating things.

→ Makes study of different objects easy and more meaningful rather than studying each other separately.

→ Helps to understand similarities and dissimilarities among objects.
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