NCERT Solutions Class 6th Science Chapter – 2 Sorting Materials into Groups Notes

April 19, 2022

NCERT Solutions Class 6th Science Chapter – 2 Sorting Materials into Groups

Textbook	NCERT
Class	6^th
Subject	Science
Chapter	2^nd
Chapter Name	Sorting Materials into Groups
Category	Class 6th Science
Medium	English
Source	Last Doubt

NCERT Solutions Class 6th Science Chapter – 2 Sorting Materials into Groups Notes In this Chapter We Will read about Materials, Classification, Basis of grouping, The smooth and rough surface, Soluble substances, Buoyancy, Transparency and Conduction of electricity etc. and More much. you have provided easy notes which use in your study make progress in education.

NCERT Solutions Class 6th Science Chapter – 2 Sorting Materials into Groups

Chapter – 2

Sorting Materials into Groups

Notes

Materials – The matter of which an object is made is called material.
For example, glass, steel, wood, etc.

• There is a vast variety of objects everywhere.

• All objects around us are made up of one or more materials.

• A thing can be made of different materials.

• Many things can be made from the same material.

Classification: The process of sorting and grouping things according to some basis is’called classification.

Basis of grouping: We can group materials on the basis of the similarities and differences in their properties.
• Each material has its own properties, that may differ from others. However, some properties may be common to one or more materials.

Uses of a material: Uses of a material depend on its properties and the purpose for which it has to be used. Metals have lustre while non-metals generally have no lustre.

Smooth and rough surface: Some materials feel smooth when touched
Example: mirror and things made of metals; whereas, some other materials feel rough when touched; for example, a piece of stone.

Hardness and softness: Materials which can be pressed easily are called soft while some other materials which cannot be pressed are called hard.
Example: cotton is soft while wood is hard.

Solubility – The maximum amount of solute that dissolves in a specific amount of solvent at a specific temperature is known as solubility.

Soluble substances: Substances that get dissolved in water are called soluble substances.

Insoluble substances: Substances which do not dissolve in water are called insoluble substances.

Miscible: Those liquids which mix well with water are said to be miscible.

Immiscible: Substances which do not mix well with water are called immiscible.

Solubility of gases: Solubility of gases in water is very less.
• Oxygen gas which is dissolved in water, is very important for the survival of aquatic plants and animals.

Buoyancy: Some materials float in water while others sink

(i) Materials like sand, sugar and salt sink in water.
(ii) Materials like wax, oil and wood float on water.

Transparency – transparency can be defined as the degree to which a substance can be seen through a specific object Transparent objects are substances or materials through which other objects can be seen. Translucent materials are those through which objects can be seen, but not clearly.
example: glass, butter paper

Opaque: Materials through which we are not able to see are called opaque. For example, wood, iron, gold.

Translucent: Materials through which things are only partially visible are called translucent. For example, butter paper, old glass door.

Transparent: Materials through which things can be seen are called transparent. For example, glass, water, air, test tube.

Things are grouped together for convenience and to study their properties

Hard: Materials which cannot be pressed easily are called hard e.g., stone.

Insoluble: Materials which do not dissolve in water are called insoluble.

Lustre: Some materials have a special shine on them which is called lustre.

Material: The matter of which an object is made, is called material. For example, glass, steel, wood, etc.

Metals: Materials which have certain properties like, lustre, malleability, ductility and are sonorous, good conductors of heat and electricity, are called metals.

Opaque: Materials which do not allow light to pass through them are called opaque.

Rough: Some materials have uneven surface and feel rough on touching.

Soluble: Materials which dissolve in water are called soluble.

Translucent: Materials which partially allow light to pass through them are called translucent.

Transparent: Materials which allow light to pass through them are called transparent.

Grouping On The Basic Of Common Properties:

Objects are made of different materials. One material can be used to make different objects. This is possible because different types of materials have different properties. We have to choose materials with the right properties based on what we want to use it for.

Example : a chalk made of wood or plastic would be of no use because it cannot be used to write on the blackboard. Materials have different properties like roughness, lustre, transparency, solubility, flotation, attraction towards a magnet, conduction of heat, and conduction of electricity. Let us study these properties one by one.

Roughness: Materials can be rough or smooth. Rough materials have bumps or ridges on their surface, which can be felt by touching them. Smooth materials lack these bumps. Examples of rough materials are rocks, sandpaper, and bark of a tree.

Lustre: Lustre is the shine of a material. All metals in pure state are shiny and said to possess lustre. This property of metals is widely used for making jewellery and other decorative articles. Materials like gold, silver, and bronze have lustre

State: All substances are made up of matter. Matter exists in three states – solid, liquid, and gas.

Flotation: Certain materials float on water whereas others sink. This property of a material to float on water is called flotation. Generally, materials like wood, leaf, and feather float on water whereas rock and metal sink.

Attraction towards a magnet: Materials that are attracted to a magnet are called magnetic materials. This property is called magnetism. Objects made of iron are attracted to a magnet. In addition to iron, nickel and cobalt are also attracted to a magnet.

Conduction of heat: If you observe the utensils in your kitchen, you will notice that though most of them are made of metals, their handles are made of wood or hard plastic.

insulators of heat – Materials that allow heat to flow through them are called conductors of heat whereas those that do not allow heat to flow through them are called insulators of heat.

Generally, metals are conductors of heat whereas non-metals like wood, plastic, glass, bamboo, air, and paper are insulators of heat.

Conduction of electricity:

We get electricity in our homes through cables and wires. An electric cable consists of a number of metal wires with or without a plastic covering.

The metal wires conduct or transmit electricity whereas the plastic covering do not. Materials that conduct electricity are called conductors. Materials that do not conduct electricity are called insulators.
Example: metals are conductors of electricity; wood, air, and plastic are insulators.

Q. 1. Why do we need to group materials? Give one reason.

Ans – We often group materials for our convenience.
It helps to describe their properties.

Q2. Suggest two bases on which we can group objects.

Ans –
(i) Material used in making the object, e.g. wood or metal/plastic.
(ii) Material of the object is soft or hard, or substance is soluble or insoluble in water.