Sorting Materials into Groups: science class six
Object around us
There is large number of objects around us. These objects may be living or nonliving. Some are natural, some are manmade, some are hard and some are soft. Different things have different shape and size. Chair, table, cycle, toys, stone, books, cloth, fan, computer and many other things are found around us.
All these things are made of one or more types of materials. Some commonly used materials are:
Metal, Paper, Plastic, Cotton, Synthetic fibre, Jute, Clay, Cement, wood, etc.
Different things contain different kind of matter. All these different kinds of matter are called materials.
Thus things are made of one or more than one materials.
Example
A Knife is made from steel or wood or plastic.
A toy is made from plastic, wood, or metals.
Vegetable is made by using raw vegetables, salt, spices and oil.
Thus steel, wood, Plastic, glass, salt, spices, vegetable, oil etc. are materials.
Materials may be natural occurring or manmade.
Examples
Cotton, Wood, marble, etc. are natural occurring materials.
Glass, steel, thermocol, Plastic, Polyster, nylone etc, are man made materials.
We can feel things by touching smelling or seeing.
Some materials are soft while some are hard. Cotton is soft in touch and stone is hard. We can recognize the hardness and softness of materials by touching them.
All materials occupy space.
A Pen placed on a table occupies space on the table.
Water in a glass occupies space on the table.
All materials have mass. All things contain one or more kinds of material. The amount of matter in any object is called its mass, So all materials have mass.
Some important properties of materials
Materials or substances can be classified on the basis of their properties.
Physical State
We can classify various materials according to their physical state. There are three physical states of material. These three states are called solid, liquid and gas.
Solid State
Stones, wood, plastic, steel, glass, salt, sand, ice, etc. are example of materials in their solid state.
Liquid
Milk, water, oil etc, are in liquid state.
Gas
Oxygen, nitrogen, carbon dioxide, steam, etc. are gases. Air is also a mixture of gases.
We can classify materials on the basis of their different property. For example
(a) Materials they are made of
(b) Metals and non metals
(c) Solubility and insolubility
(d) Floating and sinking materials
(e) Transparency i.e. transparent, opaque and translucent.
Thus, materials or substances can be classified on the basis of their properties.
We can classify materials on the basis of their solubility and insolubility characteristics in water.
Things which are soluble in water
Salt, sugar etc which are soluble in water can be kept in one group.
Things which are insoluble in water
Sand, soil, stone, chalk etc which are insoluble in water be kept in one group.
Classification on the basis of floating and sinking in water
Some materials float in water while some sinks in the water. On the basis of sinking and floating nature, things can be classified in two groups.
Floating things in the water
Wood, rubber ball, Air filled bottle etc. float on the surface of water so these can be kept in one group.
Sinking material in the water
Stone, iron ball, iron nails, bricks etc. sinks in the water so these can be kept in one group.
Classification on the basis of Transparency
The materials which allow to pass through them are called Transparent materials, glass, acrylic sheet, water and air are transparent material.
The materials which do not allow to pass through them are called opaque materials. Wood. Stone. Cardboard, metals, etc are opaque materials.
Certain materials allow only a part of the light to pass through them such materials are called translucent materials.
Oily paper or waxed paper and glass are translucent materials.
NCERT Exercise Solution
Question (1) Name five objects which can be made from wood.
Answer : Chair, door, window, bed and bat.
Question (2) Select those objects from the following which shine:
Glass bowl, plastic toy, steel spoon, cotton shirt
Answer : Objects which are shine: Glass bowl, steel spoon.
Object which are not shine: Plastic toy, cotton shirt.
Question (3) Match the objects given below with the materials from which they could be made. Remember, an object could be made from more than one material and a given material could be used for making many objects.
| Objects | Materials |
|---|---|
| Book | Glass |
| Tumbler | Wood |
| Chair | Paper |
| Toy | Leather |
| Shoes | Plastic |
Answer
| Objects | Materials |
|---|---|
| Book | Paper |
| Tumbler | Glass |
| Chair | Wood |
| Toy | Plastic |
| Shoes | Leather |
Question (4) State whether the statements given below are True or False.
(i) Stone is transparent, while glass is opaque.
Answer False
Correct Statement: Stone is opaque while glass is transparent.
(ii) A notebook has luster while eraser does not.
Answer: False
(iii) Chalk dissolves in water.
Answer False
(iv) A piece of wood floats on water.
Answer: True
(v) Sugar does not dissolve in water.
Answer: False
Correct Statement: Sugar dissolves in water.
(vi) Oil mixes with water.
Answer: False
Correct Statement: Oil does not mix with water.
(vii)Sand settles down in water.
Answer True
(viii)Vinegar dissolves in water.
Answer True
Question(5) Given below are the names of some objects and materials:
Water, basketball, orange, sugar, globe, apple and earthen pitcher
Group them as:
(a)Round shaped and other shapes
(b) Eatables and non eatables.
Answer
(a) Round shaped: Baskerball, orange, globe, apple
Other shapes: Water, sugar, earthen pitcher
(b) Eatables : water, orange, sugar, apple
Non eatables: Basket ball, globe, earthen pitcher.
Question (6) List all items known to you that float on water. Check and see if they will float on an oil or kerosene.
Answer
Wood, rubber, ball, plastic toys, etc are float on water.
Yes oil and kerosene also float on the water.
Question (7) Find the odd one out from the following:
(a) Chair, Bed, Table, Baby, Cupboard
(b) Rose, Jasmine, Boat, Marigold, Lotus
(c) Aluminium, Iron, Copper, Silver, Sand
(d) Sugar, Salt, Sand, Copper sulphate.
Answer (a) Baby
Answer (b) Boat
Answer (c) Sand
Answer (d) Sand
Extra Questions based Sorting Materials into Groups
Question (1) Write 'T' for correct and 'F' for incorrect statements-
(i) Frosted glasses are opaque.
Answer True
(ii)Water is transparent.
Answer True
(iii) Air is opaque.
Answer False
Correct Statement: Air is transparent.
(iv)Wood sinks in water.
Answer False
Correct Statement Wood floats on water.
(v) Stone floats on water.
Answer False
Correct Answer Stone sinks in water.
(vi)Grouping is done on the basis of similarities in things.
Answer True
(vii) Chair, table, stool, book shelf are grouped together because all these are made of wood.
Answer True
(viii) Salt, Sugar etc which are soluble in water can be kept in one group.
Answer True
(ix) Oil is miscible with water.
Answer True
Question (2) Fill in the blanks
(a) Stone is ________than soil.
Answer hard
(b) Stone cannot _______ on the surface of water.
Answer Float
(c) Plane glass is ____________.
Answer transparent.
(d) We cannot __________ opposite of wood.
Answer see
(e) Shoes are made from ________.
Answer leather
(f) Chalk is ___________ in water.
Answer insoluble
(g) Sugar is __________ in water.
Answer soluble
Question (3) Very short answer type questions-
(a) What is the name of three states of matter?
Answer: Solid, liquid and gas
(b) Which will float in water a small nail made of iron or a big ship made of iron?
Answer A big ship made of iron float in water.
(c) Light passes through which type of material?
Answer: Light passes through transparent material
(d) What happen if a spoonful of salt steers in a glass of water?
Answer When a spoonful of salt steers in a glass of water, salt dissolves in the glass of water.
(d) Which types of glasses are used for the windows of bathroom?
Answer Translucent glasses are used for the windows of bathroom
(e) Write the examples of solid, liquid and gas.
Answer
Solid: Stones, wood, plastic, steel, glass, salt, sand, ice etc. are example of solid
Liquid: Milk, water, oil etc, are some example of liquids.
Gases: Oxygen, nitrogen, carbon dioxide, steam, etc. are some example of gases.
(f) Write the example of soluble materials in water.
Answer Salt and sugar, etc. are soluble in water.
(g)Which type of glasses are used for spectacles?
Answer Transparent glasses are used for spectacles.
(h) Classify following in living and non–living things.
Lion, Tree, Computer, Fan and monkey.
Answer Lion, tree and monkey are living things. While computer and fan are non living.
(i) Write the name of three states of water?
Answer Solid, liquid and gas are three states of water.
Water is in liquid state.
Ice is in solid state.
Water vapour is in gaseous state.
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