Select Page

Subject:

science-chemistry

Class:

class VII

Key Concepts

natural fibre, man made fibre,selective breeding, cocoon, life cycle of silkworm, soritng, reeling, sericulture, silk moth, shearing, scouring

essential questions

1. Have you ever wondered why man chose to rear wool bearing animals and how he was inspired to get wool from them?
2. How has man been inspired by nature to get different type of fiber for his own requirements?

Remembering:

  1. What is selective breeding?
  2. What is occupational hazard?
  3. What is Sorter’s disease?
  4. Sheeps are herbivores. Give reasons
  5. What are burrs? At what stage in processing of fibre do we pick burrs.

 

understanding:

  1. Describe in detail the life cycle of a silk moth. Draw a labelled diagram
  2. Write in detail the process of converting fibres to wool.

Application:

  1. Why are woolen clothes used in winters to keep us warm?
  2. Why does it not pain the animal while shearing?
  3. Which type of fibre are made to sweaters and woolen clothes? Can you give a reason for the same.

Analysis:

  1. Why does woollen fibre an silk fibre when burnt smell like a burning of hair?
  2. When a cotton thread and paper are burnt, they smell the same. can you find the reason behind the same.
  3. Paheli wanted to buy a silk frock and went to market with her mother. There they found that the artificial silk was much cheaper. Can you give the reason why?

Evaluation:

Create: