CHAPTER- 2 SORTING MATERIALS INTO GROUPS
Notes
1. Objects around us are made of one or more materials. These materials can be glass, metals, plastic, wood, cotton, paper, rubber, and soil.
2. Sometimes an object is made of a single material, while at other times the same object may be made from several materials. Also, many different objects can be made using the same material.
3. Materials usually appear different from one another.
- Wood looks completely different from iron. Iron looks different from copper or aluminium. Still, iron, copper, and aluminium may have some similarities that are not found in wood.
4. Metal- Materials that have shine (lustre) are usually metals. Example- iron, copper, etc.
- Some metals often lose their shine and begin to look dull (non-lustrous). This happens due to reactions with air and moisture.
5. Soft- Materials are those substances that can be easily compressed or scratched; such materials are called soft materials.
6. Hard- Materials are those substances that are difficult to compress; such materials are called hard materials.
7. Soluble- Substances are those materials that completely dissolve or disappear in water; such substances are called soluble in water.
8. Insoluble- Substances are those materials that do not mix with water and do not disappear in it; such substances are called insoluble in water.
9. Some liquids mix completely with water. Some other liquids do not mix with water and, when left undisturbed for some time, form separate layers.
10. Transparent- Materials are those substances through which objects can be seen.
Example: glass, water, air, etc.
11. Opaque- Materials are those substances through which you cannot see objects.
Example: wood, cardboard, metals, etc.
12. Translucent- Such materials through which objects can be seen but not very clearly are called translucent.
EXERCISE
Question- 1. Name five objects which can be made from wood.
Answer- Five objects that can be made from wood are: 1. Table, 2. Chair, 3. Cupboard, 4. Door, 5. Toys.
Question- 2. Select those objects from the following which shine:
Glass bowl, plastic toy, steel spoon, cotton shirt.
Answer- Glass bowl, steel spoon.
Question- 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.
(1) Stone is transparent, while glass is opaque.
(2) A notebook has lusture while eraser does not.
(3) Chalk dissolves in water.
(4) A piece of wood floats on water.
(5) Sugar does not dissolve in water.
(6) Oil mixes with water.
(7) Sand settles down in water.
(8) Vinegar dissolves in water.
Answer- (1)- False, (2)- False, (3)- False, (4)- True, (5)- False, (6)- False, (7)- True, (8)- True.
Question- 5. Given below are the names of some objects and materials:
Water, basketball, Orange, Sugar, Globe, Apple and earthen pitcher group them us:
(a) Round shaped and other shapes
(b) Eatables and non eatables
Answer- (a) Round shaped- Basketball, Orange, Apple, Globe and earthen pitcher.
Other shapes- Water and sugar.
b) Eatables- Water, Orange, Apple and Sugar.
Non eatables- Basketball, Globe, earthen pitcher.
Question- 6. List all items known to you that float on water. Check and see if they will float on an oil or kerosene.
Answer- A piece of wood, a balloon, paper, a plastic bottle, a boat, etc. will float on water. Whereas a ball and a balloon will float on kerosene or oil.
Question- 7. Find the odd one out from the following:
(a) Chair, Bed, Table, Baby, Cupboard
(b) Rose, Jasmine, Boat, Marigold, Lotus
(c) Aluminium, Iron, Copped, Silver , Sand
(d) Sugar, Salt, Sand, Copper sulphate
Answer- (a)- Baby, (b)- Boat, (c)- Sand, (d)- Sand.