Tuesday , July 5 2022
NCERT 7th Class (CBSE) Science: Fibre to Fabric – Quiz

NCERT 6th Class (CBSE) Science: Fibre to Fabric

Question: Explain how jute is obtained from the jute plant.

Answer: The jute plant is normally harvested at flowering stage. The stems of harvested plants are bundled and immersed in water for 10 to 15 days. The stems rot (the process is called retting) and fibres are separated by hand. These fibres are converted into yarns to make fabrics.

Question: What are looms?

Answer: The devices on which weaving of fabrics takes place are called looms. The looms are either hand operated or power operated.

Question: What happens when a yam from a tom sock is pulled?

Answer: When we pull a yarn from a torn sock then a single yarn, gets pulled out continuously as the fabric gets unravelled. Socks are made up of knitted fabrics from a single yam.

Question: What were the materials used by people in ancient times in place of clothes?

Answer: It appears that in those days people used the bark and big leaves of trees or animal skin and furs in place of clothes.

Question: What happened when people began to settle in agricultural communities?

Answer: When people began to settle in agricultural communities then they learnt to weave twigs and grass into mats and baskets. Vines, animal fleece or hair
were twisted together into long strands. These strands were woven into fabrics.

Question: When we bum wool why do we get the smell of hair bum?

Answer: Wool is obtained from the fleece (hair) of sheep, goat, yak etc. This is the reason why burning of wool resembles the burning of hair.

Question: When we bum nylon, why we do not get the smell of burning paper or burning hair?

Answer: Nylon is a synthetic fibre made from chemicals. On burning nylon these chemicals don’t produce the smell of burning paper or hair which are natural substances.

Question: Describe the process of the formation of yarn from cotton wool.

Answer: The cotton wool is obtained from cotton plants. The cotton plants are grown in fields. They are usually grown at the places having black soil and warm climate. The fruits of the cotton plants called cotton bolls are about the size of lemons. After maturing, the bolls burst open and seeds covered with cotton fibres can b,e seen. From the cotton bolls cotton is picked by hands. Fibres are then separated from the seeds by combing. This process is called ginning of cotton. It is done by hand or by machines. These fibres are then converted into yam.

Question: Describe the process of spinning and weaving.

Answer:

  1. Spinning: The process of making yarn from fibres is called spinning. In this process fibres from a mass of cotton wool are drawn out and twisted. By this fibres come together to form a yarn. Spinning can be done by hand, by takli and charkha. On a large scale, spinning is done with the help of machines.
  2. Weaving: The process of arranging two sets of yarns together to make a fabric is called weaving. The process of weaving can be done on looms. The looms are either-hand operated or power operated.

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