# Sorting Materials into Groups Class 6 notes – Chapter 4

## CBSE Class 6 Science Notes Chapter 4 Sorting Materials into Groups

Learn from School Connect Online. In this chapter, we will learn that the things we use in our daily life are made up of different types of materials and these materials contain mass, shape. These materials are further classified based on many criteria, including their physical states, properties of materials, etc.

## The different topics covered in CBSE Class 6 Science Chapter 4 are tabulated below:

There is a different variety of objects everywhere. All objects around us are made up of different kinds of materials. Objects around us are all kinds of objects and thus identifying them is important. Doors, fans, balls, books, pens, pencils, tables are a few objects which are around us. All these differ from one another by some properties. Every object we use is made to fulfil some purpose for us. The usage of each object depends on its properties and purpose.

For example, a toy is an object to fulfil the need of a child playing, a fan to provide coolness. Hence, we can identify the objects based on their shape, size, colour and texture.

We look around and identify an object based on the colour, shape, size, texture and lustre of an object, accordingly cluster them into a similar objective cluster. Similar objective clusters are the cluster of objects having the same property and hence we can classify them as one cluster.

### Ex : 4.1 – Object around Us :

We saw that our food and clothes have so much variety in them. Not just food and clothes, there is such a vast variety of objects everywhere. We see around us, a chair, a bullock cart, a cycle, cooking utensils, books, clothes, toys, water, stones and many other objects. All these objects have different shapes, colours and uses.

### Ex : 4.2 – Properties Of Materials

• 1. The materials can be sorted into their groups based on the three states of matter :
• solids
• liquids
• gases
• 2. Sorting of  the materials are  based on their appearance.

The appearance of materials varies in :

• Colour
• Texture
• Hard
• Soft
• Lustre
• 3. Criteria used to sort the materials are based on their solubility. Solubility of materials in water depends on :
• Solubility
• Insolubility

For example :

(i). Salt and sugar are soluble in water.

(ii). Chalk and sand are insoluble in water.

• 4. Criteria used to sort the materials is based on the
• Metal

Example : Silver, Lead, Sodium

• Non – metals

Example : Coal, chalk, rubber,Iodine

• 5. Sorting the materials is based on the light transmission through objects, which includes :
• Opaque
• Translucent
• Transparent

Classification: The process of sorting and grouping things according to some basis is called classification.Materials can be classified based on several properties:

• Transparency
• Hardness
• Soluble and Insoluble
• Float and Sink

Basis of grouping: We can group materials on the basis of the similarities and differences in their properties.

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 e.g., 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; for example, cotton is soft while wood is hard.

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:

• Materials like sand, sugar and salt sink in water.
• Materials like wax, oil and wood float on water.

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 that 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 an 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:

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 the bark of a tree. A glass sheet, flower petals, and the surface of an apple are some examples of smooth surfaces.

Lustre:

Lustre is the shine of a material. All metals in a 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.

Transparency:

Materials can be grouped into three main categories based on their ability to transmit light.

## Conclusion :

• Transparent Materials that allow light to pass through them are called transparent materials.
• Translucent Materials that allow some light to pass through them are called translucent materials.
• Opaque Materials that do not allow light to pass through them are called opaque materials.
• Miscible Liquids that are soluble in water are said to be miscible in water.
• Immiscible liquids that are insoluble in water are said to be immiscible in water.
• Magnetic materials Materials that are attracted by a magnet are called magnetic materials.
• Conductors Materials that conduct heat or electricity are called conductors.
• Insulators Materials that do not conduct heat or electricity are called insulators.
• Materials have different properties that make them useful for making different objects.
• An object can be made from different materials.
• Different objects can be made from the same material.
• Materials can be rough or smooth, transparent or opaque, soluble in water or insoluble, can float on water or sink; can be a conductor or insulators of heat or electricity.

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