Class 6 Science Notes
Chapter 4 Sorting Materials Into Groups
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
Appearance
→ 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)
Visibility
→ 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.)
Electricity
→ Good conductor (Metals are good conductor ; electricity can pass through it)→ Bad conductor (non-metals ; electricity can’t pass through it)
Heat
→ 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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