Maharashtra Board Textbook Solutions

Standard 6 – Science

Chapter 6 – Substances in Daily Use

✨ 1. Fill in the blanks using proper words.

(a) Rubber made by vulcanization is a hard material.

(b) Man-made materials are made by processing natural materials.

(d) Rayon is also known as synthetic silk.

❓ 2. Answer the following questions.

(a) Why did the need for man-made materials arise?
Ans: Man continuously strives for newer and better things to make life more comfortable. Therefore, he uses natural substances to create different useful artificial materials. The production of low-cost and easily available materials helps to fulfil human needs.

(b) Which are the natural materials obtained from plants and animals?
Ans: Natural materials are obtained from both plants and animals.

Plant-origin materials: Cotton, jute, hemp, teak wood, flowers, and fruits.
Animal-origin materials: Leather, silk, lac, pearl, and wool.

(c) What is vulcanization?
Ans: Vulcanization is a chemical process in which rubber is heated with sulphur for three to four hours. This process makes the rubber stronger and harder.

(d) Which natural materials are used to obtain fibres?
Ans: Natural materials such as cotton, jute, hemp, wool, and silk are used to obtain fibres.

🔧 3. What are we used for?

(a) Soil
Ans: Soil supports all living things on Earth. It is also used for making various articles and as a building material.

(b) Wood
Ans: Wood is used for making furniture, paper, and decorative articles.

(d) Paper
Ans: Paper is used for writing, printing, and packing materials. It is also used for making currency notes.

(e) Rubber
Ans: Rubber is used for making rubber bands, erasers, toys, tyres, and many other items.

🏭 4. How is paper manufactured? Write in your own words.

Ans:

First, trees such as pine (coniferous trees) are cut down.
The bark of the logs is removed.
The wood is cut into small pieces.
These pieces are mixed with chemicals and soaked for a long time to form pulp.
After the chemical process, the fibres are separated from the pulp.
Dyes are added, and the pulp is passed through rollers.
Finally, it is dried and wound into rolls (reels).

🧠 5. Give scientific reasons.

(a) We must use cotton clothes in summer.
Ans: Cotton clothes are made from natural fibres that absorb sweat easily. This keeps the body cool and dry, and reduces the chances of skin problems. Therefore, we should wear cotton clothes in summer.

(b) We must observe economy in the use of materials.
Ans: Natural resources are limited and are getting used up due to the growing population. It takes a long time to replace them. Therefore, we must use materials carefully and avoid wastage.

(c) Saving paper is the need of the hour.
Ans: Paper is made from wood, which comes from trees. Excessive use of paper leads to cutting down more trees, causing deforestation and environmental problems like climate change. Therefore, saving paper is very important.

(d) Man-made materials have more demand.
Ans: Man-made materials are easy to use, low in cost, and available in large quantities. They are made according to our needs and are often more convenient than natural materials. Therefore, they are in high demand.

(e) Humus is a natural material.
Ans: Humus is formed by the decomposition of dead plants and animals by microorganisms in the soil. Since it is formed naturally, it is called a natural material.

🔍 6. Find out.

(1) How is lac obtained from nature?
Ans: Lac is obtained from lac insects. The female lac insect secretes a resin-like substance from its body. When this substance comes in contact with air, it hardens and forms lac.

(2) How are pearls obtained?
Ans: Pearls are formed inside the shells of certain marine animals called oysters. When a foreign particle enters the oyster, it covers it with layers of a substance called nacre. Over time, this forms a pearl. In cultured pearl farming, a small bead is inserted into the oyster, and layers are formed around it to produce pearls.