Textbook Solution: Fiber to Fabric | Class 7 Oxford Science: Chapter Notes, Worksheets & Tests PDF Download

A. Choose the correct option.

1.
Ans: (c) Cow

2.
Ans: (c) Bactrian

3.
Ans: (a) spring

4.
Ans: (b) caterpillars

5.
Ans: (a) anthrax

B. Fill in the blanks with the correct words.

1.
Ans: Mohair wool is obtained from the Angora goat.

2. 
Ans: The process of sorting and grouping wool is called grading.

3. 
Ans: The wool is packed into bales and sent to the mills

4. 
Ans: The four stages in the life cycle of a silk moth are egg, larva, pupa and adult.

5.
Ans: Different kinds of silk moths give us different varieties of silk.

6. 
Ans: Tussar, Mooga, and Kosa are three varieties of silk.

C. 

1.
Ans:

D. Name the following

1.
Ans: Fabric

2.
Ans: Wool

3.
Ans: Shearing

4.
Ans: Pupa

5.
Ans: Sericulture

E. Answer the following questions.

1.
Ans: Four breeds of animals that give good quality wool are sheep, goat, rabbit, and camel. Wool from sheep is soft and of high quality. Wool from goat, particularly Cashmere and Angora goats, is also of high quality. Wool from rabbit, particularly Angora rabbit, is very fine and expensive. Camel wool, especially from the Bactrian camel, is soft and fine.

2.
Ans: The coat of animals helps it to stay warm by trapping air in between its spaces, thus providing insulation.

3.
Ans: Mohair wool is obtained from the Angora goat. It is light, durable, and warm and is widely used to make sweaters and soft furniture coverings. Cashmere wool is a fine quality wool obtained from the Cashmere goat, it is luxuriously soft and provides great warmth.

4.
Ans: Wool production involves shearing, scouring, grading, dyeing, drying, and making the wool into fabric. Shearing is the process of removing hair or fur from animals. Scouring is the process of washing the wool to remove dirt, dust, and grease. Grading is the process of sorting and grouping wool according to its quality. Dyeing is the process of colouring the wool. Drying is the process of removing extra water from the wool after it has been washed and dyed. The wool is then made into fabric at the mills.

5.
Ans: Shearing is beneficial to sheep as it removes the fur that makes them feel hot in the summer.

6.
Ans: Diagram of the life cycle of a silk worm: egg, larva, pupa, adult moth. [Student is expected to draw the diagram]

7.
Ans: Sericulture is the rearing of silkworms for the commercial production of silk. The process of silk production involves selecting healthy silk moths for breeding, feeding the larvae with mulberry leaves, allowing the larvae to spin cocoons, and then harvesting the cocoons. The cocoons are put in boiling water to kill the caterpillar inside and loosen the silk fibre. The fibres are then pulled from the cocoons, twisted together to make a strong thread, and woven into fabric.

8.
Ans: Health hazards faced by workers in sericulture include infections from handling dead worms, blisters and wounds from dipping hands into hot water, backaches and spine problems from standing for long hours, eye strain, and respiratory infections from poor air circulation and fumes of boiling cocoons.