SORTING MATERIALS INTO GROUPS
All objects are made of one or more materials. These materials may be glass, metal, plastics, wood cotton paper, mud, and soil.
Material –
The substance or substances of which a thing is made or composed.
Properties of Material-
We choose a material to make an object depending on its properties and the purpose for which the object to be made or to be used. Some properties are discussed here.
(1) Appearance – Materials look different from each other. Iron looks different from wood. Some materials are lustrous while some lose their shine.
(2) Hardness – You can easily be scratched some materials, While some cannot be scratched so easily. Materials that can be scratched easily are called soft while some other materials which are difficult to compress are called hard.
(3)Soluble au Insoluble?-Some substances have completely disappeared or dissolved in water, these substances are called soluble in water, other substances do not mix with water and do not disappear even after w stir for a long time, these substances are insoluble in water.
(4) Objects may float or sink in water –Some of the materials which do not mix in the water floated to the surface of the water.
(5) Transparency – Those substances through which things can be seen are called transparent. Example Glass, water, air, etc.
- Opaque materials – These materials through which we are not able to see, these materials are called opaque materials. Example- wood, metal container, etc.
- Translucent –The materials through which an object can be seen but not called Translucent. Example-oily patch on paper, sunglasses, etc.
EXERCISE
1. Name five objects which can be made from wood.
Answer:
Five objects are
- Chair
- table
- Bed
- Door
- Box
2. Select those objects from the following which shine: Glass bowl, plastic toy, steel spoon, cotton shirt
Answer:
Glass bowl and steel spoon are the things that shine.
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.
| Objects | Material |
| Book | Glass |
| Tumbler | wood |
| Chair | Paper |
| Toy | Leather |
| Shoes | Plastics |
Answer:
| Objects | Material |
| Book | Paper |
| Tumbler | Glass |
| Chair | wood |
| Toy | Plastics |
| Shoes | Leather |
4. State whether the statements given below are True or False.
(i) Stone is transparent, while glass is opaque.
(ii) A notebook has luster 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.
Answer:
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:
(a) Round shaped and other shapes (b) Eatables and non eatables
Answer:
(a)Round shaped-
- basketball,
- orange,
- globe,
- apple,
Other shapes-
- earthen pitcher
(b) Eatables-
- Orange,
- Sugar,
- apple
Non eatables-
- basketball,
- earthen pitcher,
- globe,
- water
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) wood
(b) Plastic
(c) balloon
(d) Thermocol balls
(e) leaf
(f)empty bottle
They float on oil and 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
(b) Boat
(c) Sand
(d) Sand