סיבים לבדים - כיתה 7 מדעים

In this course, we will discuss :
Q.1. Name two types of fibers with examples.
Q.2. Give two examples each of plant fibers and animal fibers.
Q.3. Why sheep, goat, yak and some other animals have a thick coat of hair?
Q.4. Write the different types of fibers that form the hair of sheep.
Q.5. What is the meaning of selective breeding?
Q.6. The fleece of sheep is not the only source of wool. Comment.
Q.7. What do you mean by rearing of sheep?
Q.8. What is the meaning of sheep farming or sheep husbandry?
Q.9. Whether sheep are herbivores. Comment.
Q.10. What are the various steps involved in processing of fibers into wool?
Q.11. What is the meaning of shearing, scouring, sorting, and clearing of burrs?
Q.12. How many times, sheep are sheared in a year?
Q.13. Shearing is avoided in winters. Why?
Q.14. Hairs of sheep are removed during hot weather. Why?
Q.15. Whether shearing hurts the sheep? Comment.
Q.16. The people involved in sorting of hair may suffer from a disease. Name that disease.
Q.17. What is the meaning of sericulture?
Q.18. Which country is the world leader in production of silk?
Q.19. Write a note on the life history of silk moth.
Q.20. How many times, the silkworm shed their skin in the larva stage?
Q.21. The caterpillar secretes a fiber which hardens when exposed to air. That fiber is made of which substance?
Q.22. What is the meaning of cocoon?
Q.23. What the caterpillars eat?
Q.24. Write a note on rearing of silkworms?
Q.25. How the fibers is taken out from the cocoon?
Q.26. What is the meaning of reeling of the silk?
Q.27. Write a few lines on health hazards in silk industry.
Q.28. Silk worm is a useful insect. Comment.
Q.29. Which animals wool is commonly available in the market?
Q.30. For what purpose, rearing of sheep is done?
Q.31. What happens if a sheep is not shorn?
Q.32. Why some animal welfare activists criticize sericulture?
Q.33. Write the difference between natural silk and artificial silk.
Q.34. To which class, animal fiber or plant fiber, artificial silk belongs to?
Q.35. Why caterpillars need to shed their skin when they grow bigger but humans do not? Do you have any idea?
Q.36. Ella wanted to buy a silk frock and went to the market with her mother. There they found that the artificial (synthetic) silk was much cheaper and wanted to know why? Do you know why? Find out.
Q.37. Paheli went to the market to buy sarees for her mother. She took out a thread from the edge of the two sarees shown by the shopkeeper and burnt them. One thread burnt with a smell of burning hair and the other burnt with the smell of burning paper. Which thread is from a pure cotton saree and which one from a pure silk saree? Give reason for your answer.
Q.38. Why cotton garment cannot keep us as warm in winter as a woolen sweater does?
Q.39. Which stage in the life cycle of silk moth is called cocoon?
Q.40. Why caterpillars should not be collected with bare hands?
Q.41. Name the stage next to caterpillar in the life cycle of silk moth.
Q.42. Two fibers are made up of proteins. Name them.
Q.43. Which stage in the lifecycle of silkworm will be affected immediately if the mulberry bush dies suddenly? Clarify with reason.
Q.44. Why are the eggs of a silkworm kept below 18oC during winter?
Q.45. What is the suitable temperature for an egg to hatch into a larva?
Q.46. Silk is called the queen of the fibers, why?
Q.47. Farmers keep the silkmoth’s eggs in a cold place, why?
Q.48. Wool is obtained from which body part of sheep?
Q.49. Can silk-moths fly?
Q.50. Can silk-moths fly?
Q.51. Someone told Paheli that an animal called ‘Vicuna’ also gives wool. Can you tell her where this animal is found?
Q.52. Write down the features of silk.
Q.53. Explain short the four stages of life cycle of silkworm.
Q.54. You must be familiar with the following nursery rhymes?
‘Baa baa black sheep, have you any wool.’
‘Mary had little lamb, whose fleece was white as snow.’
Answer the following:
ii) Which parts of the black sheep have wool?
ii) What is meant by the white fleece of the lamb?
+ many important MCQs and Fill in the blanks.