Materials Around Us
Concept: Classification of Materials
- We are surrounded by various objects, which may be living or non-living things.
- There are many non-living things that we use in our day-to-day lives.
- These objects may vary in texture, shape, size, etc. The substances which are used to make these objects are called materials.
- Materials can be defined as the elementary constituents of the things we see, touch and use for different purposes.
Need for classification:
- Every object has its properties. They are made up of various kinds of materials. It is not easy to study all of them separately. Hence, they are classified into groups.
- Classification means sorting or placing objects in different groups based on their texture, properties or the material used.
- Classification has the following benefits—
- It helps us study similar objects together.
- It helps us analyse the materials that can be replaced with other options available when required.
- It allows us to study the similar properties of different materials together.
- It helps us choose a suitable material according to its use.
- A chair can be made using metal, wood and fabric, etc. But they do not have the same properties and cannot be used in the same conditions. Classification helps us understand this difference.
Classification of materials:
The materials around us can be classified as natural or man-made based on their source—
- Natural materials: The materials which we get from nature.
- Man-made materials: The materials which are synthesised artificially using raw material by humans.
Example : Wood, fibre, etc.
Example : Paper, plastic, etc.
- These materials are available in nature and can be used for various purposes based on their properties.
- Natural materials can be classified as follows based on their sources—
- Materials from plants:
- We get the following materials from plants—
- The materials obtained from plants can be used for a variety of purposes, some of which are mentioned below—
- Wood is used for making furniture and as a raw material for constructing buildings and railway lines.
- Wood pulp is used to make paper.
- Fibres, like cotton and jute, are used to make clothes.
- Medicinal plants are used to make medicines.
- Resins like latex are used to make rubber.
- Cereals, pulses, fruits and vegetables are used as food.
- Dry wood is used as fuel.
- Materials from animals:
- We get the following materials from animals—
- The materials obtained from animals are used for various purposes, some of which are mentioned below—
- Meat, egg and honey are used as food.
- Animal fibres, like wool, silk and fur, are used to make clothes.
- Animal waste is used for the production of biogas. Also, dry cow dung cakes are used as fuel.
- Feathers and oyster pearls are used for ornamental purposes.
- Leather is used for making shoes, belts, bags etc.
- Materials from the Earth
- The Earth is a source of various materials like rocks, minerals, salts, etc.
- The materials that we get from Earth are called abiotic materials.
- Materials obtained from Earth are used for the following reasons—
- Metals are extracted from minerals and turned into different objects. Example : Iron is used for making rods, copper is used for making wires, and gold is used for making ornaments.
- Rocks obtained are used for doing house interiors, like marble, granite, etc. Also, some rocks like ruby, sapphire, etc., are gemstones used for making jewellery.
- Salt that we use in our food is obtained by evaporating seawater.
Fruits, cereals, pulses, fibres, wood, wood pulp, resins, etc.
Egg, honey, meat, fibre, feathers, pearls, leather and animal waste.
Materials that originate from living organisms like plants and animals are also called biotic materials.
- The materials made by man using raw materials are called man-made or artificial materials.
- Humans make these materials using naturally occurring materials such as latex, wood, rocks, soil, metals, water, minerals, crude oil, etc.
- Plastic, rubber, glass, purified metals, chemicals, polyester, paper, etc., are some man-made materials.
- Plastic, rubber, etc., are now used as basic materials for making toys, toothbrushes, hairbands, water bottles etc.
- Polyester and nylon threads are used for making tents, raincoats, sarees, shirts etc.
- Glass made in factories is used for making windows, mirrors, utensils etc.
- Paper is used for making books, notebooks, newspapers etc.
Some of their uses are given below—
From natural to man-made:
- All natural things we get cannot be used directly.
- Some of them can be used after making small changes. Example : Making a pot using clay and water.
- Some materials are suitable for use only after processing in factories and industries. Example : Polybags, plastic, glass, metal, etc.
- Vast resources are used in making the materials we use. Hence, the resources should be used judiciously.
Raw material: A material that has not been changed in any way.
Biotic: Something which has life or is related to life.
Man-made materials are better than natural materials—
Although some man-made materials are better than natural ones, they are sometimes harmful to nature as they are non-biodegradable. They also use large amounts of energy and resources for formation.