Materials Around Us | Class 6 Science Notes

6.3 What are the Different Properties of Materials?

This section delves into various properties of materials that help in their classification and use. It begins by observing the appearance of materials, noting differences in texture, colour, and shine. Students collect samples of materials like paper, wood, chalk, copper wire, aluminium foil, brass, bronze, and steel, and observe their lustre (shine), texture (rough or smooth), and colour. Materials with shiny surfaces are called lustrous and are usually metals like iron, copper, zinc, aluminium, and gold. However, some metals lose their lustre due to air and moisture, appearing dull. Non-lustrous materials like paper, wood, rubber, and jute do not shine.

The section explains that not all shiny materials are metals; some are polished or coated to appear shiny. Next, it discusses hardness and softness by asking students to press or scratch materials. Hard materials are difficult to compress or scratch (e.g., stones, iron), while soft materials are easily compressed or scratched (e.g., eraser, sponge). This property is relative; for example, rubber is harder than sponge but softer than iron.

Students perform Activity 6.5 to classify objects as hard or soft based on feel and identify their materials. The section then explores transparency, translucency, and opacity through a story where children hide behind different materials. Transparent materials (glass, water, air) allow clear vision through them; translucent materials (butter paper, frosted glass) allow partial vision; opaque materials (wood, cardboard, metals) do not allow vision through them. Activity 6.6 helps classify objects accordingly.

Further, the section investigates solubility in water. Through Activity 6.7, students mix sugar, salt, chalk powder, sand, and sawdust in water to observe which materials dissolve (are soluble) and which do not (are insoluble). It explains that water dissolves many substances, playing a vital role in bodily functions. The section also touches on the solubility of liquids and gases in water, noting that oxygen dissolves in water, essential for aquatic life.

Finally, the section introduces the concepts of mass and volume through Activity 6.8, where students weigh identical cups filled with different materials (water, sand, pebbles) to compare heaviness. Mass quantifies the amount of matter, measured in grams (g) or kilograms (kg). Volume is the space occupied by matter, measured in litres (L) or millilitres (mL). These properties are common to all materials.

📊 Diagram: Images include various materials showing lustre and non-lustre; sports balls; objects for grouping; materials illustrating transparency, translucency, and opacity; soluble and insoluble materials in water; weighing cups with different materials.

🧪 Activity: Activity 6.5: Observe hardness or softness of objects; Activity 6.6: Classify objects as transparent, translucent, or opaque; Activity 6.7: Explore solubility of materials in water; Activity 6.8: Measure and compare mass of materials.

🔗 Connection: Leads to understanding the fundamental concept of matter in the next section.

Table on page 8 (8×3)

Table on page 10 (3×3)

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