Classify the following fibres as natural or synthetic:
nylon, wool, cotton, silk, polyester, jute
Natural fibres: Wool, Cotton, Silk, Jute.
Wool: We obtain wool from sheep and other animals. A fibre that is obtained from the animals are called natural fibres. Cotton: We obtain cotton from the cotton plants. Cotton is a soft fibre that grows in a ball. As we obtain it from the plants; is a natural fibre. Silk: We obtain silk from the silkworm. The best silk is obtained from the cocoon. So we can say that it is a natural fibre. Jute: Jute is obtained from the stem of the jute plant. That is why it is also a natural fibre.
Synthetic fibres: Nylon, Polyester
Nylon: It is man- made fibre. It is a thermoplastic silky material generally used for making rope and thread. Polyester: It is the derived form of coal, petroleum and water that’s why it is called synthetic fibre.
Draw (a) a leaf, (b) a taproot and (c) a flower, you have studied for Table 7.3.
You are given an iron strip. How will you make it into a magnet?
Name two foods each rich in:
(a) Fats
(b) Starch
(c) Dietary fibre
(d) Protein
A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. Can the change in POP be reversed?
Tick (√) the statements that are correct.
(a) By eating rice alone, we can fulfill nutritional requirement of our body. ( )
(b) Deficiency diseases can be prevented by eating a balanced diet. ( )
(c) Balanced diet for the body should contain a variety of food items. ( )
(d) Meat alone is sufficient to provide all nutrients to the body. ( )
List all items known to you that float on water. Check and see if they will float on an oil or kerosene.
Name the part of the plant which produces its food. Name this process.
Why can a pace or a footstep not be used as a standard unit of length?
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
Name two items that are made from coconut fibre.
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 Materials
Book Glass
Tumbler Wood
Chair Paper
Toy Leather
Shoes Plastics
Indicate true (T) and false (F) among the following sentences.
(a) The movement and locomotion of all animals is exactly the same. ( )
(b) The cartilages are harder than bones. ( )
(c) The finger bones do not have joints. ( )
(d) The fore arm has two bones. ( )
(e) Cockroaches have an outer skeleton. ( )
Explain why the bulb would not glow in the arrangement shown in Fig. 12.13.
Would the bulb glow after completing the circuit shown in Fig. 12.14 if instead of safety pin we use an eraser?
(a) Which kind of garbage is not converted into compost by the redworms?
(b) Have you seen any other organism besides redworms, in your pit? If yes, try to find out their names. Draw pictures of these.
What is the composition of air?
Some changes are listed in the following table. For each change, write in the blank column, whether the change can be reversed or not.
S.No. | Change | Can be reversed (Yes/ No) |
---|---|---|
1 | The sawing of a piece of wood | |
2 | The melting of ice candy | |
3 | Dissolving sugar in water | |
4 | The cooking of food | |
5 | The ripening of a mango | |
6 | Souring of milk |
How will you prove that air supports burning?
List all items known to you that float on water. Check and see if they will float on an oil or kerosene.
Where are poles of a bar magnet located?