Materials Around Us | Science Grade 6 CBSE

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Six properties of materials

Every material can be described by its properties. Tap each one to see what it means and how you can test it at home.

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The three big ideas

An object is a thing; the material is what it is made of. The same object can be made from different materials (a spoon of steel, wood or plastic), and one material can make many objects (glass → tumbler, window, bangle).
We group materials by their properties so we can study them and choose the right one for each job.
Appearance – lustre: clean metals like iron, copper and gold are lustrous (shiny); wood, chalk and paper are dull.
Hardness: hard materials (iron, stone, diamond) are not easily compressed or scratched; soft materials (cotton, sponge, clay) dent easily. Diamond is the hardest natural material known.

Transparent – light passes through, so you can see clearly: clean glass, clean water, air.
Translucent – light passes only partly, so things look blurred: butter paper, frosted glass, oiled paper.
Opaque – no light passes through, so you cannot see through them: wood, metal, cardboard, stone.

Try it. Shine a torch through different things in a dark room.

Through glass the light passes brightly (transparent); through butter paper it is dim and fuzzy (translucent); through a thick book nothing passes (opaque). The same test sorts any material.

Solubility: some materials dissolve in water (salt, sugar) – soluble; others do not (sand, chalk powder) – insoluble. A solution looks clear, but the material is still there (taste salty water!).
Liquids with water: some mix completely (miscible – like vinegar); some do not (immiscible – like oil, which floats on top).
Even gases dissolve: oxygen dissolves in water – that is how fish breathe through their gills.
Floating & sinking: materials that are light for their size float (wood, thermocol, a sealed empty bottle); denser ones sink (an iron nail, a stone).

Common mistakes: thinking a dissolved material has “disappeared” – salt is still in the solution; and thinking “heavy always sinks” – a huge log floats while a tiny nail sinks, so shape and material matter, not just weight.

Where you’ll meet it

Materials at work

Cleaning drinking water

Insoluble dirt and sand are removed by filtering water through cloth or sand beds, because they do not dissolve. Knowing soluble from insoluble is the first step in making water safe.

Choosing the right material

We build walls from hard stone and brick, stuff pillows with soft cotton, and fit transparent glass in windows. Each choice matches a property of the material to the job it must do.

Boats that carry tonnes

A fishing boat is shaped hollow so it traps air and spreads its weight, letting heavy iron and people float. The same metal as a solid lump would sink – shape changes everything.

Check yourself

Competency quiz

Modelled on the competency-based pattern — MCQ, assertion–reason and case studies, testing whether you can use the ideas, not just recall them.

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