If you are preparing solve these of Ch-4 Sci. What is classification? ...
Classification is the process of organizing materials into groups based on their similar characteristics. There are several ways of classifying materials, such as appearance, hardness or softness, solubility, heaviness or lightness, and transparency, translucency, or opaqueness. Materials can be classified as lustrous or non-lustrous, soft or hard, soluble or insoluble, transparent, translucent, or opaque.
- Lustrous materials have a shiny appearance, such as metals like gold, silver, copper, aluminium and iron, and metal alloys such as steel, stainless steel, and brass.
- Non-lustrous materials have a dull appearance, such as paper, wood, chalk, cotton, plastic, rubber, and cardboard.
- Soft materials can be easily compressed, cut, moulded, or scratched, such as sponge, cotton, wool, foam, rubber, candle wax, butter, chalk, clay, feathers, flour, and skin.
- Hard materials cannot be easily compressed, cut, moulded, or scratched, such as iron, steel, wood, stone, brick, glass, bone, teeth, and diamond.
- Soluble materials can dissolve in water, such as common salt, sugar, washing soda, potassium permanganate, copper sulphate, alum, milk, lemon juice, alcohol, and glycerine.
- Insoluble materials cannot dissolve in water, such as chalk powder, saw-dust, sulphur, glass, plastic, paper, flour, wax, mustard oil, groundnut oil, coconut oil, kerosene, and petrol.
- Transparent materials allow almost all the light to pass through them, such as glass, air, polythene, groundnut oil, and alcohol.
- Translucent materials allow only a small amount of light to pass through them, such as oiled paper, tissue paper, muddy water, and clouds.
- Opaque materials do not allow any light to pass through them, such as cardboard, wood, bricks, metal, and books.