Contents
Chemistry Topics cover a wide range of subjects, including atomic structure, chemical reactions, and the periodic table.
How do we see objects around us?
A thing that can be seen and touched is called an object. An object is called ‘vastu’ or ‘cheez’ in Hindi. The matter of which an object is made is called material. Material is called ‘padarth’ in Hindi.
We see a large number of objects around us. There are human beings, animals, birds and insects around us. We also have different types of plants and trees around us. The objects like table, chair, books, blackboard, chalk, paper, clothes, shoes, water, bicycle, football, toys, utensils, and sand are also around us. We can go on adding more and more objects to this list of objects which we can see around us. In fact, there is a large variety of objects around us.
Some of these objects are natural (which occur in nature as such), whereas other objects are man-made (or artificial). All these objects are of different shapes, sizes and colours. They also have different properties. In order to understand objects around us, it is necessary to classify them into groups. We will now discuss how the various objects are classified.
Classification of Objects
If we go to a provision store in the market, we will find that the various objects being sold in the shop are arranged in groups on the shelves. For example, all kinds of soaps are placed together at one place and all types of biscuits are placed together at another place. Similarly, other objects like pulses, spices, dry fruits, chocolates, tooth-brushes, and tooth-pastes, etc., are all placed in their respective places in the shop. The advantage of placing the various objects group-wise is that it becomes very easy to locate a particular object in the shop.
For example, if we ask the shopkeeper for a particular brand of soap, then the shopkeeper goes to the shelf containing soaps only and takes out the required soap from it. We say that the shopkeeper has arranged the various objects in ‘groups’ or that he has classified the objects. If, however, all the objects like soaps, biscuits, pulses, spices, dry-fruits, chocolates, tooth-brushes and tooth-pastes, etc., are all mixed up in the shop, it will not be easy for the shopkeeper to locate a particular soap immediately. We can now write a definition of classification as follows:
The sorting of objects into groups with each group having its own characteristic properties, is called classification of objects. All the objects having similar characteristic properties are placed in one
group during classification. And the objects having different properties are placed in different groups. For example, all types of soaps have similar characteristics, so all types of soaps are placed in one group at a shop. Similarly, all types of biscuits have similar characteristics, so all types of biscuits have also been placed together in one group. But the characteristics of soaps are different from those of biscuits, therefore, soaps and biscuits have been placed in different groups. We classify the objects because it gives us the following advantages:
- The classification of objects into groups makes it easier to locate them and work with them.
- The classification of objects into groups helps in understanding them. This is because if we know the properties of any one member of the group, we can get an idea of the properties of the other members of this group.
Basis of Classification of Objects
The classification of various objects into groups can be done on the basis of their similarities and dissimilarities such as: living or non-living; plant or animal; nature of material; use, colour, shape, size, appearance, hardness, texture, etc. Thus, the various objects can be classified (or grouped) as follows:
- All the objects can be classified into two main groups: Living objects and Non-living objects.
- Living objects can be classified further into two groups: Plants and Animals.
- Non-living objects can be classified into many groups on the basis of their nature of material, use, colour, shape, size, appearance, hardness, texture, etc.
It should be noted that the classification of objects into groups can be done only when the objects have some similarities and some dissimilarities (differences). The objects cannot be classified into groups if all of them are similar or all of them are dissimilar (different). Thus, if we have some objects which are similar in all respects, they cannot be classified into different groups.
Classification of Objects as Living and Non-Living
All the living objects need food, water and air for their survival whereas non-living objects do not require these things. Based on this difference, all the objects around us can be classified into two groups: living objects and non-living objects. As an example, let us classify the following objects into living objects and non-living objects:
Table, Toy, Dog, Clothes, Rose, Algae, Pencil, Knife, Shoes, Hydrilla, Grass-hopper, Blackboard,
Cactus, Wool, Earthworm, Tree, Fish, Feather, Nail, Lien
If we look at these objects carefully, we will find that out of these objects, dog, rose, algae, hydrilla, grasshopper, cactus, earthworm, tree, fish and hen are living objects. On the other hand, table, toy, clothes, pencil, knife, shoes, blackboard, wool, feather and nail are non-living objects. So, we can classify (or divide) all the above objects into two groups as ‘living objects’ and ‘non-living objects’ as follows:
Living objects
Dog
Rose
Algae
Hydrilla
Grasshopper
Cactus
Earthworm
Tree
Fish
Hen
Non-Living objects
Table
Toy
Clothes
Pencil
Knife
Shoes
Blackboard
Wool
Feather
Nail
Classification of Living Objects as Plants and Animals
All the plants can make their food by using carbon dioxide, water and sunlight whereas animals cannot make their food in this way. Based on this difference, all the living objects can be classified into two groups: plants and animals. Let us classify the following living objects into plants and animals:
Dog, Rose, Algae, Hydrilla, Grasshopper, Cactus, Earthworm, Tree, Fish, Hen
Now, out of these living objects, rose, algae, hydrilla, cactus and tree are plants whereas dog, grasshopper, earthworm, fish and hen are animals. So, we can classify these living objects into two groups, plants and animals, as follows:
Classification of Non-Living Objects
The non-living objects can be classified on the basis of the material (of which they are made), their uses, colour, shape, size, appearance, hardness and texture, etc. We will give an example of the classification of non-living objects on the basis of the nature of their material. Consider the following non-living objects:
Table, Nail, Beaker, Toy, Chair, Utensils, Test-tube, Ruler, Bed, Magnet, Funnel, Mug, Door,
Coin, Mirror, Polythene bag
Out of these objects, table, chair, bed and door are made of wood; nail, utensils, magnet and coin are made of metals; beaker, test-tube, funnel and mirror are made of glass whereas toy, ruler, mug and polythene bag are made of plastics. So, we can classify all the above objects into four groups on the basis of nature of material of which they are made: objects made of wood; objects made of metal; objects made of glass and objects made of plastics. This classification is shown on the next page.
We will now answer some questions based on the classification of objects or grouping of objects.
Example Problem 1.
Given below are the names of some objects and materials :
Water, Basket ball, Orange, Sugar, Globe, Apple, Earthen pitcher Group them as :
(a) Round shaped (or nearly round shaped), and Other shapes.
(b) Eatables and Non-eatables.
Answer:
(a) Round shapes
(or Nearly round shapes) :
Basket ball
Orange
Globe
Apple
Earthen pitcher
Other Shapes:
Water
Sugar
(b) Eatables:
Water
Orange
Sugar
Apple
Non-eatables:
Basket ball
Globe
Earthen pitcher
Example Problem 2.
Find the odd one out from the following :
(a) Chair, Bed, Table, Baby, Cupboard.
(b) Rose, Jasmine, Boat, Marigold, Lotus.
Answer:
(a) Chair, Bed, Table and Cupboard are non-living objects made of wood whereas baby is a living object. So, the odd one is baby.
(b) Rose, Jasmine, Marigold and Lotus are living objects (plants), whereas boat is a non-living object. So, the odd one is boat.