G. Answer these questions.
1. Which chemicals are used in the manufacture of synthetic fibres?
2. State the factors which determine the quality of wool extracted from a sheep.
3. What do you mean by occupational hazard?
4. Explain sorter's disease
5. Name different stages in the life cycle of silk moth.
6. Write the steps involved in the production of silk and also name the discoverer of silk.
Answers
Answer:
1} The principle ingredient used in the manufacture of polyester is ethylene, which is derived frompetroleum. In this process, ethylene is the polymer, the chemical building block of polyester, and the chemical process that produces the finished polyester is called polymerization.
2}Many factors determine the quality (and value) of wool. These include fiber diameter, crimp, yield, color, purity, and staple length and strength. Fiber diameter, also called fineness, is the actual measurement of the thickness of the wool fiber.
3}The Fair Labor Standards Act (FLSA) prohibits minors under age 18 years old to work in any occupation that it deems to be hazardous. Among these occupations are excavation, manufacturing explosives, mining, and operating many types of power-driven equipment.
4}Sorter's Disease is another name for Anthrax. It is caused by the bacteria Bacillus anthracis. Historically, anthrax was called wool sorter's disease because individuals who sorted wool of infected animals contracted the disease.
5}The female silk moth lays about 300 to 400 eggs at a time. The eggs hatch and the caterpillars or silkworms emerge. Inside the cocoon, the silkworm enters the second stage of its life (called the pupa) and then the third and final stage to become an adult moth
6}In order to obtain silk, mulberry trees are cultivated, silkworms are reared and their cocoons are collected to get silk fibres. the various steps involved are :
1) REARING OF SILKWORMS
2)PROCESSING OF COCOONS TO OBTAIN SILK FIBRES
3)CONVERTING SILK FIBRE INTO SILK CLOTH