This MCQ module is based on: Properties of Materials — Hardness and Lustre
TOPIC 20 OF 46
Properties of Materials — Hardness and Lustre
🎓 Class 6
Science
CBSE
Theory
Ch 6 — Materials Around Us
⏱ ~14 min
🌐 Language: [gtranslate]
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6.3 Properties of Materials — Why Each Material Is Special
After grouping materials in Part 1, Madam Vidya asked a tricky question: "Why do we make windows out of glass and not cardboard? Why are pillows filled with cotton and not stone?" The answer lies in something called a property.
A property of a material is a special feature (hardness, shine, transparency, solubility, density, etc.) that decides how we use it. Every material has its own unique bundle of properties.
6.3.1 Hardness — How Easily Can It Be Scratched?
Press your thumb into a cotton ball — it sinks in. Now press your thumb on a stone wall — nothing happens. That's hardness in action.
Hard materials
Cannot be easily scratched, cut, or squeezed. Examples: iron, stone, glass, diamond.
Soft materials
Can be easily pressed, scratched or squeezed. Examples: cotton, sponge, rubber, clay.
Activity 6.3 — The Nail Test for Hardness L3 Apply
You need: a clean iron nail, and these objects: a chalk piece, a wooden ruler, a piece of soap, a small stone, a metal spoon.
- Press the point of the nail against each object and try to scratch it gently (ask a grown-up to help).
- Observe: does the nail leave a mark? Or does it just slide off?
- Arrange the objects from softest to hardest in your notebook.
Predict: Which of chalk, soap, wood, stone and metal do you think will be the hardest? The softest?
Softest → hardest: soap → chalk → wood → stone → metal. The nail easily marks soap and chalk, makes a small scratch on wood, barely scratches stone, and does not scratch the metal spoon (the spoon is made of steel — harder than an iron nail).
How We Use Hardness
Choosing between hard and soft is a daily decision. Builders want hard materials like stone, concrete and iron rods because a house must stand firm for years. But when you go to sleep, you want soft materials — a cotton pillow, a foam mattress — so your body rests comfortably.
6.3.2 Lustre — The Shine of a Material
Lustre is the natural shine that some materials have, especially when their surface is clean and fresh.
Shiny (lustrous) materials: most metals — gold, silver, copper, freshly polished iron, as well as glass and diamonds. These reflect light well, which is why mirrors are made of glass with a metal coating at the back.
Dull (non-lustrous) materials: wood, paper, stone, cotton, clay. Light does not bounce off them smoothly, so they look dull.
Tip: Metals lose their shine over time because a thin layer of dust, rust or tarnish covers them. Rub an old coin with lemon and salt — the shine returns! That's because the dull layer is removed and the fresh metal is visible again.
6.3.3 Transparency — Can We See Through It?
Hold a clean glass tumbler in front of your eye. You can see your friend clearly across the table. Now hold a wooden board — nothing can be seen through it. Light passes through some materials and gets blocked by others. This gives us three groups:
Transparent
All light passes through. You can see things clearly on the other side. Examples: clean glass, clear water, clear plastic sheet.
Translucent
Some light passes, but images are blurry or hazy. Examples: frosted glass, butter paper, oiled paper, thin curtains.
Opaque
No light passes. You cannot see anything through it. Examples: wood, metal, cardboard, stone, the human body.
Activity 6.4 — The Torch Test L3 Apply
You need: a torch (or phone flashlight), and these materials — a clean plastic sheet, butter paper (or tracing paper), a thin cotton cloth, a piece of cardboard, a glass tumbler, a wooden scale, an oiled paper.
- In a dark room, hold each material in front of the torch.
- Observe: do you see the full torch, a blurry glow, or nothing at all?
- Record each material as Transparent / Translucent / Opaque.
Predict: Will oiled paper let more or less light through than dry paper?
Transparent: clean plastic sheet, glass tumbler. Translucent: butter paper, oiled paper, thin cotton cloth. Opaque: cardboard, wooden scale. Oiled paper is more translucent than dry paper because the oil fills the tiny gaps in the paper and lets light pass more smoothly.
Where We Use Each Type
| Property | Why useful | Everyday use |
|---|---|---|
| Transparent | We need to see through clearly | Windows, spectacles, test tubes, bulbs, watch face, car windscreen |
| Translucent | We want some light but also privacy | Bathroom windows, lampshades, office partitions, window blinds |
| Opaque | We want to block light and see | Walls, doors, clothes, curtains, school bags, shoes |
Interactive: Property Tester L3
Click any object below and the tester will tell you its three properties — hardness, lustre and transparency.
Choose an object:
Competency-Based Questions
Sheeta is helping her mother choose curtains for two rooms. For the drawing room, Mom wants soft sunlight to enter but also wants privacy from the street. For Sheeta's study room, Mom wants the brightest possible light so Sheeta can read clearly.
Q1. Which type of material — transparent, translucent or opaque — should Sheeta's mother pick for the drawing room curtain? L3
Answer: B. Translucent cloth lets some soft light in but blocks clear vision from outside — perfect for privacy + light.
Q2. Name one hard material and one soft material. Give one everyday use of each. L2
Hard: Iron — used for building rods, gates, tools. Soft: Cotton — used for clothes, pillows, mattresses.
Q3. Give two examples each of transparent, translucent and opaque materials. L1
Transparent: clean glass, clean water. Translucent: butter paper, frosted glass. Opaque: wood, metal.
Q4. A coin that was shiny last year now looks dull. Has it changed material? Explain. L4
No — it is the same metal. A thin layer of dust and tarnish has formed on the surface, which hides the natural lustre. Cleaning the coin brings the shine back.
Q5. State True or False: "A material can be both soft and shiny at the same time." Justify with an example. L5
True. Aluminium foil is soft (you can crumple it easily) yet it is shiny (has lustre). Properties are independent — one material can score differently on each.
Assertion – Reason
Assertion (A): Windows are usually made of glass.
Reason (R): Glass is transparent, so we can see through it clearly.
Answer: A. Transparency is the key reason windows use glass — R perfectly explains A.
Assertion (A): Iron is a hard material.
Reason (R): A fingernail can easily scratch iron.
Answer: C. Iron is indeed hard (A true), but a fingernail cannot scratch iron (R false) — which is exactly because iron is harder than a fingernail.
Assertion (A): Butter paper is called translucent.
Reason (R): Butter paper lets some light through but you cannot see objects clearly through it.
Answer: A. Partial light + blurry view is the very definition of translucent — R explains A.
Frequently Asked Questions — Properties of Materials — Hardness and Lustre
What does the topic 'Properties of Materials — Hardness and Lustre' cover in Class 6 Science?
The topic 'Properties of Materials — Hardness and Lustre' is part of NCERT Class 6 Science Chapter 6 — Materials Around Us. It covers the key ideas of hardness, softness, lustre, transparency, opaque, translucent, properties of materials, explained through everyday examples, labelled diagrams and hands-on activities from the NCERT Curiosity textbook. Class 6 students learn simple definitions, see why each idea matters in daily life, and try short experiments and observations. The lesson uses easy language, colourful pictures and small questions so that young learners build a strong base for higher classes and for competency-based questions in CBSE school tests.
Why is 'Properties of Materials — Hardness and Lustre' important for Class 6 NCERT Science?
'Properties of Materials — Hardness and Lustre' is important because it builds the first ideas of science that Class 6 students will use again in Class 7, 8 and beyond. NCERT Chapter 6 — Materials Around Us — introduces hardness and connects it to things children already see at home, at school and in nature. Learning this topic helps students ask better questions, understand simple news about science, and score well in CBSE tests that use competency-based questions. The chapter also supports NEP 2020 by encouraging curiosity, observation and learning by doing rather than only reading and memorising.
What are the key ideas students should remember from Properties of Materials — Hardness and Lustre?
The key ideas in 'Properties of Materials — Hardness and Lustre' for Class 6 Science are: hardness, softness, lustre, transparency, opaque, translucent, properties of materials. Students should be able to say each term in their own words, give one or two easy examples from daily life, and draw a small labelled diagram where needed. A good way to revise is to make flashcards, write a short note in the science notebook, and solve the NCERT in-text and exercise questions of Chapter 6. Linking every idea to something seen at home or school — in the kitchen, garden, playground or sky — makes these ideas easy to remember for unit tests and the annual CBSE examination.
How is Properties of Materials — Hardness and Lustre taught using activities in NCERT Curiosity Class 6?
NCERT Curiosity Class 6 Science teaches 'Properties of Materials — Hardness and Lustre' through an inquiry-based approach using Predict–Observe–Explain activities. Students first make a guess, then try a small experiment with safe, easily available materials, and finally explain what happened and why. This matches the NEP 2020 focus on learning by doing. For Chapter 6 — Materials Around Us — the textbook has hands-on tasks, labelled pictures and thinking questions built for Bloom's Taxonomy Levels 1 to 6. Teachers use these activities, along with competency-based questions (CBQs) and assertion–reason items, to check real understanding instead of only rote learning.
What real-life examples of hardness can Class 6 students see at home?
Class 6 students can see hardness at home in many simple ways linked to 'Properties of Materials — Hardness and Lustre'. Kitchens, school bags, playgrounds, the garden and the night sky are full of examples that match NCERT Chapter 6 — Materials Around Us. For example, students can look at food labels, watch changes while cooking, try safe activities with water, magnets or shadows, and observe the Sun, Moon and weather each day. Keeping a small science diary — with the date, what was observed and a quick drawing — turns daily life into a mini science lab. These real-life links make concepts easy to remember and help in answering competency-based questions in CBSE Class 6 Science.
How does 'Properties of Materials — Hardness and Lustre' connect to other chapters of Class 6 Science?
'Properties of Materials — Hardness and Lustre' connects to many other chapters in NCERT Class 6 Science Curiosity. The ideas of hardness come back when students study related topics like diversity in the living world, food, magnets, measurement, materials, temperature, water, separation, habitats, natural resources and the solar system. For example, what students learn here helps them build mental pictures for later chapters and for Class 7 and Class 8 Science. Teachers often ask cross-chapter questions in CBSE exams to check if students can use what they learned in Chapter 6 — Materials Around Us — in new situations. This linked approach matches the NEP 2020 and NCF 2023 focus on holistic, competency-based learning.
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