Question Answers For All Chapters – General Science Class 6
Substances in Daily Use
Exercise
1. Fill in the blanks using proper words.
(a) Rubber made by vulcanization is a man-made material.
(b) Man-made materials are made by processing natural materials.
(c) Nylon thread was developed simultaneously in New York and London.
(d) Rayon is also known as synthetic silk.
2. Answer the following questions.
(a) Why did the need for man-made materials arise?
Answer – The need for man-made materials arose because natural materials were not always available in large quantities. Man-made materials are cheaper, stronger, and easier to produce in large amounts.
(b) Which are the natural materials obtained from plants and animals?
Answer – Natural materials obtained from plants: Cotton, jute, wood, rubber, and silk.
Natural materials obtained from animals: Wool, leather, and silk.
(c) What is vulcanization?
Answer – Vulcanization is a process in which rubber is heated with sulphur to make it stronger and more durable. This process makes rubber useful for making tires, balls, and other items.
(d) Which natural materials are used to obtain fibres?
Answer – Natural fibres are obtained from cotton plants, silk from silkworms, and wool from sheep.
3. What are we used for?
Answer –
(a) Soil – Used for growing plants and making clay pots.
(b) Wood – Used for making furniture, paper, and houses.
(c) Nylon – Used for making ropes, fishing nets, and clothes.
(d) Paper – Used for writing, books, and packaging.
(e) Rubber – Used for making tires, erasers, and toys.
4. How is paper manufactured? Write in your own words.
Answer – Paper is made from trees. First, the bark is removed from the wood. Then, the wood is cut into small pieces and soaked in water with some chemicals to make a soft pulp. This pulp is then pressed, dried, and rolled into thin sheets to make paper.
5. Give scientific reasons.
(a) We must use cotton clothes in summer.
Answer – Cotton clothes keep us cool in summer because they absorb sweat and allow air to pass through.
(b) We must observe economy in the use of materials.
Answer – Materials like paper and plastic take a long time to decompose, so we should use them wisely to reduce waste and protect nature.
(c) Saving paper is the need of the hour.
Answer – Paper is made from trees, and cutting trees harms the environment. By saving paper, we can save trees and protect nature.
(d) Man-made materials have more demand.
Answer – Man-made materials like plastic and nylon are cheaper, stronger, and can be made in large quantities, making them more useful in daily life.
(e) Humus is a natural material.
Answer – Humus is formed from the decayed remains of plants and animals in the soil. It helps plants grow by making the soil fertile.
6. Find out.
(1) How is lac obtained from nature?
Answer – Lac is a natural resin obtained from the secretions of tiny insects called lac insects found on trees. It is used to make bangles and polish.
(2) How are pearls obtained?
Answer – Pearls are obtained from oysters that live in the sea. When a small grain of sand enters an oyster, it covers it with layers of a shiny substance, forming a pearl.
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