Class 6 Science

Main Points For Quick Revision Chapter 3 Of 6th Science

1. Cleaning of food is essential to make it fit for eating.
2. Husk is separated from heavier seeds of grain by handpicking.
3. Filtration can be used to separate components of a mixture of an insoluble solid and a liquid.
4. Sedimentation separates the heavier components from a mixture of solid particles and water, by means of gravitational force.
5. Threshing, winnowing, handpicking, sieving, decantation, loading, filtration and evaporation are important methods of cleaning food.
6. Common salt is manufactured by the method of evaporation.
7. A solution is a mixture of two substances. The substance in large quantity is the solute.
8. Magnetic separation can be used to separate iron from sand.

1. Variety In Fabrics

This part of the content gives you an idea about different types of fabrics and the manufacturing process of making fabric from fibres. In ancient times, when stitching was not known, people used the bark, big leaves of tree and animal skin around their bodies to cover themselves. Later on, they began weaving twigs, grasses together into long strands and covered themselves. Now in modern civilization, clothes that we wear are made of different types of fabrics. Such as cotton, silk, wool, synthetic. Remember, fabrics are made of yarns and yarns are made of many strands. If we gently try to pull a small yarn from fabric or cloth, then we can see that is made up of long thin strands.

2. Fibres

This paragraph helps you to understand the type of fibres that uses to make different types of clothes. Fibres are obtained from natural as well as man-made sources. The thin strands of thread that we see in clothes are called fibres. Fibres that comes from plants and animals sources, called Natural fibres. Such as cotton, jute, wool, the fleece of ship, silk etc. The fibres which is made from chemical substances, called synthetic fibres. Such as nylon, rayon, acrylic etc.

3. Some Plant Fibres

As we know, all the animals and plant have fibres in their bodies. The fibres which we get from animal sources called animal fibres. The fibres which we get from plant sources called plant fibres. Coconut, jute and cotton are the examples of plant fibres. But remember, all fibres are not suitable for making clothes. Coconut fibres are tough and can only be used for making ropes in mattress. Jute fibres are very coarse, rough and not suitable for skin. Cotton is soft fabric and evaporates sweat and keeps the body cool and comfortable. It easily absorb water. So, globally people prefer to wear cotton fabric. Cotton is obtained from the fruits of the cotton plants. That cotton fruits bolls are handpicked when they ripped. Then with the help of ginning process cotton fibres are separated from seeds.

4. Spinning Of Cotton Yarn

In this part of the content describes the different making processes of yarns from fibres. As we know, Mahatma Gandhi popularised that use of charkha as a part of the Independence movement. Generally, in the spinning process, Takli and Charkha and many other devices were used by the people. The process of making yarn from fibres is called ‘spinning’. In this process, the fibres from a mass of cotton wool are drawn out and twisted. This process brings the fibres together to form a long and twisted thread called ‘yarn’.

5. Yarn To Fabric

There are many ways by which fabrics are made from yarns. The two main processes are weaving and knitting. In the weaving process, arranging two sets of yarns together to make a fabric is called weaving. You might have noticed that a piece of fabric is made up of two sets of yarns arrange together. Generally, in the knitting process, the making of fabric by interlocking loops of single yarn with knitting needles or machines. You have to remember that socks and many other clothing items are made of knitted fabrics.

6. History Of Clothing Materials

We know that earlier Indians in Gangetic plains used cotton fabric. In Egypt, the ancient people grew cotton as well as flax to make fabrics. When the stitching was not known, people simply wrapped the fabric around various parts of their body. With the invention of the sewing needle, people started stitching fabrics to make clothes. Now, today we have many variations of dresses to wear.

1. Paheli wants to present her friend a gift made of plant-fibre. Which out of the following will she select?
(a) Jute bag (b) Woollen shawl (c) Silk saree (d) Nylon scarf
2. Which of the following materials did people use in ancient times for making clothes?
(i) Leaves of trees (ii) Newspaper (iii) Metal foils (iv) Animal skins and furs
(a) (i) and (ii) (b) (i) and (iii) (c) (ii) and (iii) (d) (i) and (iv)
3. Boojho went to a cloth shop. There he found a fabric which was smooth to touch, had vibrant colour and shine. The fabric could be
(a) Cotton (b) Wool (c) Silk (d) Jute
4. Beera is a farmer. His field has black soil and the climate is warm. Which fibre yielding plant should he grow in his field?
(a) Jute (b) Cotton (c) Coconut (d) Wool
5. Boojho wants to make yarn from fibre at home. Which of the following will he use to carry out the task?
(a) Powerloom (b) Handloom (c) Charkha (d) Knitting needles
6. State whether the following statements are true or false. If false, correct them.
(a) Silk is a plant fibre.
(b) Jute is obtained from the leaves of a plant.
(c) Weaving is a process of arranging two sets of yarn together.
(d) Cotton yarn on burning gives an odour similar to that of a burning paper.
7. Once, Paheli visited a tailor shop and brought home some cuttings of fabric to study their properties. She took two pieces and found that one of the pieces were shrinking when it was burnt with a candle. However the other did not shrink on burning. Can you help her to find out which of the two was a cotton fabric and which a silk fabric?