Sorting Materials into Groups

1. Sorting Materials into Groups INTRODUCTION     There is a massive form of objects everywhere. All objects around us are made from one or more materials. A thing are often made from different materials. Many things may be made up of an equivalent material. Eg: Pencil, Pen, Dustbins, Desk and chair and so on. Properties of Materials Materials are often classified as:    Solid Liquid Gas Some examples are: Solid→ Stone, Sand and steel Liquid→ Milk, Oil and Water

2. Gas → Oxygen, Steam and Nitrogen Classification on Basis of Look or Appear Materials are often classified on the basis of how they look or appear to be. Some of the materials are:   Some materials have lustre, which may be a very gentle sheen or soft glow to them Others are plain and dull looking. Classification on the basis of Soft or Hard Materials that may be easily compressed or scratched are called Soft.  For example: Paper, clothes, vegetables etc Materials that can't be scratched and are difficult to compress are termed as Hard.  For example: Wood, Plastic, Steel etc. Classification on the basis of Soluble or Insoluble Materials which will be dissolved in water upon stirring are said to be soluble materials.  For example: Salt, Sugar Materials that can't be dissolved in water despite how much we stir them are said to be insoluble materials.  For Example: Clothes and Stones Note: Not just solid materials, even liquids have the property of being soluble or insoluble. For Example: lemon juice can easily dissolve in water while oil doesn't dissolve and deposits as a thin layer on the uppermost layer of water. Objects may float or sink in water There are some insoluble objects or materials which sink to rock bottom of the surface when dissolved in water while some other float on the surface of the water. For Example:

3.   Corks and Leaves float in water. Coins and Rocks sink in water. Objects may float or sink in water There are some insoluble objects or materials which sink to rock bottom of the surface when dissolved in water while some other float of the water. on the surface For Example:   Corks and Leaves float in water. Coins and Rocks sink in water. Transparent or Opaque Objects or materials which may be seen through are said to be transparent objects.  For Example: Some Plastics, Glass Objects and materials through which things are often seen but only partially are called translucent objects.  For Example: Frosted Glass and Butter paper Objects which can't be seen through are referred to as opaque objects.

4.  For Example: Wood, Metals, and Cardboard Metals and Non-Metals   Electricity can pass through it such metals are good conductor. Electricity cannot pass through it such Non metals are bad conductor. What is meaning of Classification The process of sorting and grouping things consistent with some basis. What are the uses of materials?   Uses of a material depend upon its properties and therefore the purpose that it's to be used. Metals have lustre whereas non-metals generally haven't any lustre. What are the explanations we want to group objects? We need to group objects for variety of reasons:   Materials are grouped together on the idea of similarities and differences in their properties. Things are grouped together for convenience and to review their properties. NCERT SOLUTIONS 1. Name five objects which can be made from wood. Solution: Table Chair Doors Desk Box 2. Select those objects from the following which shine: Glass bowl, plastic toy, steel spoon, cotton shirt Solution: The objects that shine are:

5. Glass bowl, Steel Spoon 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. Solution: ObjectsMaterial Book Paper, Wood Tumbler Glass, wood, plastic Chair wood, plastic Toy Glass, Wood, Paper, Plastics, Leather Shoes Leather, Plastic 4. State whether the statements given below are True or False. (i) Stone is transparent, while glass is opaque. (ii) A notebook has lustre while eraser does not. (iii) Chalk dissolves in water. (iv) A piece of wood floats on water. (v) Sugar does not dissolve in water. (vi) Oil mixes with water. (vii) Sand settles down in water. (viii) Vinegar dissolves in water. Solution: i) False ii) False iii) False iv) True v) False vi) False vii) True viii) True 5. Given below are the names of some objects and materials: Water, basket-ball, orange, sugar, globe, apple and earthen pitcher. Group them as:

6. (a) Round shaped and other shapes (b) Eatables and non-eatables Solution: (a) Round shaped – Basketball, Orange, Globe, Apple, Earthen pitcher Other shapes – Water, Sugar (b) Eatables – Water, Orange, Sugar, Apple Non eatables – Basketball, Globe, Earthen pitcher 6. List all items known to you that float on water. Check and see if they will float on an oil or kerosene. Solution: Few items that float on water are as follows: Sponge’s piece, Plastic bottle, Paper’s piece, Thermocol’s piece, Wood, Plastic ball, Cork However, these items will not float on an oil or kerosene 7. Find the odd one out from the following: a) Chair, Bed, Table, Baby, Cupboard b) Rose, Jasmine, Boat, Marigold, Lotus c) Aluminum, Iron, Copper, Silver, Sand d) Sugar, Salt, Sand, Copper sulphate Solution: a) Baby – others are made up of wood b) Boat – others are flowers c) Sand – others are metals d) Sand – others are soluble in water