Materials Around Us — Class 6 Science
Curiosity · Chapter 6
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5- Mathematics
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- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
- Space weighted by chapter size
- Charts from the book's own data
- Traps corrected
Chapter summary
Key ideas & terms
- Material
- Any substance that is used to create or make an object, such as paper, wood, metal, glass, or plastic.
- Classification
- The method of arranging objects or materials into groups based on a common property.
- Lustrous and non-lustrous
- Lustrous materials have a shiny surface and are usually metals, while non-lustrous materials are dull, such as paper, wood, and rubber.
- Transparent, translucent, opaque
- Transparent materials can be seen through clearly, translucent materials are seen through but not clearly, and opaque materials cannot be seen through at all.
- Soluble and insoluble
- Soluble materials dissolve in water, such as sugar and salt, while insoluble materials do not dissolve, such as sand and chalk powder.
- Matter
- Anything that occupies space and has mass; mass is measured in grams and kilograms, and volume (the space occupied) in litres and millilitres.
Extra questions & answers
What is a material?
A material is any substance that is used to create or make an object, such as paper, wood, metal, glass, or plastic.
What is classification?
Classification is the method of arranging objects or materials into groups based on a common property that they share.
What is the difference between lustrous and non-lustrous materials?
Lustrous materials have a shiny surface and are usually metals such as iron and copper, while non-lustrous materials are dull, such as paper, wood, and rubber.
Are all shiny materials metals?
No; not all that glitters is gold. Some materials are made shiny by polishing or coating them with plastic, wax, or other materials, so they may not be metals.
How are materials grouped by how much we can see through them?
They are grouped as transparent (seen through clearly, like glass), translucent (seen through but not clearly, like butter paper), and opaque (cannot be seen through, like wood).
What is the difference between soluble and insoluble materials?
Soluble materials dissolve completely in water, such as sugar and salt, while insoluble materials do not dissolve, such as sand and chalk powder.
What is mass?
Mass is the property by which an object is heavier or lighter; an object with more mass is heavier, and its units are grams and kilograms.
What is volume?
Volume is the space occupied by matter; it is measured in litres and millilitres, and its SI unit is the cubic metre.
What is matter?
Matter is anything that occupies space and has mass; all materials around us, such as water, sand, and a cup, are examples of matter.
How are mass and units like kg and mL written correctly?
A space is left between the number and the unit, the symbol has no plural 's' or full stop, kg is lowercase, and mL is written with lowercase m and uppercase L.
Let us play
1. Find the companion. Link the following words by putting arrows between words that have a connection. Iron Transparent Copper Solid Bottle Plastic Lustrous Wood Opaque Glass
This is a word-connection game. One correct way to link the words by their properties is: Lustrous → Iron and Copper (iron and copper are metals with a shiny, lustrous surface); Transparent → Glass and Bottle (a glass bottle is an example of a transparent object through which we can see clearly); Opaque → Wood (wood does not allow light to pass, so we cannot see through it); Solid → Iron, Copper, Wood, Glass, Plastic and Bottle (all are solids, they have fixed shape and occupy space); Plastic → Bottle (a bottle can also be made of plastic). Arrows can be drawn to show these connections, for example Iron → Lustrous ← Copper and Glass → Transparent ← Bottle and Wood → Opaque.
2. Win the ‘Word-hub’ The following words from the chapter like lustrous, non-lustrous, soluble, insoluble, hard, soft, matter, mass, transparent, opaque, volume and translucent are picked up. Grid Students should randomly choose nine words from the given list and write them in the grid. Then, the facilitator either reads the definition of a word or the word itself (randomly) from the given list. The learners have to tick if the particular word is there in the grid. Whoever finishes ticking off all nine words first will shout out ‘Hurray!’ That person will be the winner if his/her words are marked correctly.
This is a bingo-type game to revise the new words. Make a 3x3 grid on paper and write any nine words you like from the list of twelve given words. For example you could write lustrous, hard, soluble, transparent, opaque, matter, mass, volume and translucent. The teacher will then call out either the word itself or its meaning, such as shiny surface for lustrous or that which occupies space and has mass for matter. If you have that word in your grid, you tick it. The first person to tick all nine words in his or her grid correctly and shout Hurray wins.
Let us enhance our learning
1. Visit your kitchen and observe how your parents have organised various edibles. Can you suggest a better sorting method? Write it in your notebook.
In most kitchens edibles are kept by type and use: grains and pulses together, spices together, oils and pickles together, and fruits and vegetables apart in cool places. A better sorting method is to group by properties and need. For example, group all soluble items like sugar and salt in airtight, labelled, transparent jars so you can see the amount; group perishable items like milk and vegetables in the refrigerator; group heavy and less used items like large grain bags on lower shelves and daily use items like tea and spices at eye level. You can also group by material of container to avoid spoilage. This helps to find things easily, keeps food safe, and saves space.
2. Unscramble the letters (Column I) and match with their properties (Column II). (i) T R E M A T
Unscrambled word is MATTER. It matches with (b) Occupies space and has mass. Matter is anything that has mass and occupies space, and is measured in
2. Unscramble the letters (Column I) and match with their properties (Column II). (ii) U L S B E L O
Unscrambled word is SOLUBLE. It matches with (d) Mixes completely in water. A soluble material disappears on stirring in water, like sugar or salt.
2. Unscramble the letters (Column I) and match with their properties (Column II). (iii) T N E R P A S N A R T
Unscrambled word is TRANSPARENT. It matches with (a) Objects can be seen clearly through it. Examples are clear glass, water and air.
2. Unscramble the letters (Column I) and match with their properties (Column II). (iv) E R U S T L
Unscrambled word is LUSTRE or LUSTROUS. The form LUSTRE matches with (c) Shiny surface. Materials with lustre have a shiny appearance, usually metals like gold, copper and aluminium on their fresh surface.
3. The containers which are used to store materials in shops and at home are usually transparent. Give your reasons for this.
Transparent containers are used because we can see the material inside clearly without opening the container. This helps to identify the item quickly, to know how much is left, to check colour, quality and freshness, and to find the correct spice or grain easily in a shop or kitchen. It also saves time and avoids mixing up similar-looking materials.
4. State whether the statements given below are True [T] or False [F]. Correct the False statement(s). (i) Wood is translucent while glass is opaque. [ ]
False [F]. Correct statement: Wood is opaque and glass is transparent. Wood does not allow light to pass so we cannot see through it, while clear glass allows us to see clearly through it.
4. State whether the statements given below are True [T] or False [F]. Correct the False statement(s). (ii) Aluminium foil has lustre while an eraser does not. [ ]
True [T]. Aluminium is a metal and has a shiny lustrous surface, whereas an eraser made of rubber is non-lustrous and dull.
4. State whether the statements given below are True [T] or False [F]. Correct the False statement(s). (iii) Sugar dissolves in water whereas sawdust does not. [ ]
True [T]. Sugar is soluble in water and disappears on stirring, while sawdust is insoluble and floats or settles without dissolving.
4. State whether the statements given below are True [T] or False [F]. Correct the False statement(s). (iv) An apple is a matter because it occupies no space and has mass. [ ]
False [F]. Correct statement: An apple is matter because it occupies space and has mass. All matter must have both mass and volume.
5. We see chairs made up of various materials, such as wood, iron, plastic, bamboo, cement and stones. Following are some desirable properties of materials which can be used to make chairs. Which materials used to make chairs fulfil these properties the most? (i) Hardness (does not bend or shake on sitting even after long use).
For hardness, materials like wood, iron, cement and stone are best. They are hard and cannot be compressed or bent easily, so the chair remains strong and does not shake after long use.
5. We see chairs made up of various materials, such as wood, iron, plastic, bamboo, cement and stones. Following are some desirable properties of materials which can be used to make chairs. Which materials used to make chairs fulfil these properties the most? (ii) Lightweight (easy to lift or to take from one place to another).
For lightweight, plastic and bamboo are best. Their mass is less compared to iron or stone for the same volume, so the chair is easy to carry. Wood is heavier than plastic but lighter than iron and stone.
5. We see chairs made up of various materials, such as wood, iron, plastic, bamboo, cement and stones. Following are some desirable properties of materials which can be used to make chairs. Which materials used to make chairs fulfil these properties the most? (iii) Does not feel very cold when sitting during winters.
Wood, plastic and bamboo do not feel very cold in winter because they do not conduct heat away from the body quickly. Metal like iron and stone feel very cold to touch in winter as they are good conductors of heat.
5. We see chairs made up of various materials, such as wood, iron, plastic, bamboo, cement and stones. Following are some desirable properties of materials which can be used to make chairs. Which materials used to make chairs fulfil these properties the most? (iv) Can be cleaned regularly and made to look new even after long use.
Plastic and iron with paint or coating can be cleaned easily with water and look new for a long time because they have smooth, non-porous surfaces. Wood can also be polished to look new but needs more care, while bamboo and cement are more difficult to keep shiny.
6. You need to have containers for collection of: (i) food waste, (ii) broken glass and (iii) wastepaper. Which materials will you choose for containers of these types of waste? What properties of materials do you need to think of? (i) food waste
For food waste, use a container that is non-porous, waterproof, easy to clean, not easily broken, and preferably has a lid to avoid smell. Plastic with a lid or a metal bin with coating is good because food waste contains water and may be sticky. It should be opaque so waste is not visible and should not react with the waste.
6. You need to have containers for collection of: (i) food waste, (ii) broken glass and (iii) wastepaper. Which materials will you choose for containers of these types of waste? What properties of materials do you need to think of? (ii) broken glass
For broken glass, use a hard, strong, puncture-proof container that will not be cut by sharp edges. A thick metal or hard plastic box with a lid is suitable. It should be labelled and preferably opaque and rigid, so glass pieces do not pierce through like they would with a polythene bag or paper bag.
6. You need to have containers for collection of: (i) food waste, (ii) broken glass and (iii) wastepaper. Which materials will you choose for containers of these types of waste? What properties of materials do you need to think of? (iii) wastepaper
For wastepaper, a simple container made of cardboard, cloth, jute or light plastic is enough. It should be dry, lightweight and large because paper is light and dry. It does not need to be waterproof or airtight, just strong enough to hold paper and keep it dry.
7. Air is all around us but does not hinder us from seeing each other. Whereas, if a wooden door comes in between, we cannot see each other. It is because air is and the wooden door is . Choose the most appropriate option: (i) transparent, opaque (ii) translucent, transparent (iii) opaque, translucent (iv) transparent, translucent
The correct option is (i) transparent, opaque. Air is transparent because we can see clearly through it, while a wooden door is opaque because we cannot see at all through it.
8. Imagine you have two mysterious materials, X and Y. When you try to press material X, it feels rigid and does not change its shape easily. On the other hand, material Y easily changes its shape when you press it. Now, when you mix both materials in water, only material X dissolves completely, while material Y remains unchanged. What can materials X and Y be? Can you identify whether material X is hard or soft? What about material Y? Justify your answer.
Material X is hard and soluble in water. For example, it could be common salt, sugar, or washing soda crystal. It feels rigid and does not change shape on pressing, so it is hard. It also disappears completely when stirred in water, so it is soluble. Material Y is soft and insoluble in water. For example, it could be sponge, rubber, wax, or wet clay. It changes shape easily when pressed, so it is soft. It does not dissolve in water and remains as it is, so it is insoluble.
9. (i) Who am I? Identify me on the basis of the given properties. (a) I have lustre.
I am a metal like gold, copper, aluminium or iron. Metals have a shiny lustrous appearance on their fresh surface.
9. (i) Who am I? Identify me on the basis of the given properties. (b) I can be easily compressed.
I am a soft material like sponge, rubber eraser, cotton or clay. Soft materials can be pressed or scratched easily.
9. (i) Who am I? Identify me on the basis of the given properties. (c) I am hard and soluble in water.
I am a hard solid that dissolves in water, like common salt or sugar crystal or alum. I am hard because I cannot be pressed easily, but I disappear in water.
9. (i) Who am I? Identify me on the basis of the given properties. (d) You cannot see clearly through me.
I am a translucent material like frosted glass or butter paper. I allow light to pass but objects seen through me appear blurry, not clear.
9. (i) Who am I? Identify me on the basis of the given properties. (e) I have mass and volume but you cannot see me.
I am air or any gas. Air is matter, it has mass and occupies space, but it is transparent and invisible although we can feel it.
9. (ii) Make your own ‘Who am I?’
Here is an example: I am hard, opaque and non-lustrous, I am used to make tables and chairs, and I do not dissolve in water. Who am I? Answer: Wood.
10. You are provided with the following materials—vinegar, honey, mustard oil, water, glucose and wheat flour. Make any two pairs of materials where one material is soluble in the other. Now, make two pairs of materials where one material remains insoluble in the other material.
Soluble pairs with respect to water: Glucose in water, honey in water, and vinegar in water all mix completely. For example, 1) Glucose + water — glucose dissolves completely in water. 2) Vinegar + water — vinegar mixes completely with water. Insoluble pairs: 1) Mustard oil + water — mustard oil does not mix with water and forms a separate layer. 2) Wheat flour + water — wheat flour does not dissolve, it forms a cloudy suspension and settles when left undisturbed.