Chapter 2 science-exploring diversity of matter by its physical properties

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Five main classes of materials

• Ceramic, Metal, Glass, Plastic, Fibres.

Properties of Ceramics- melting point, conductor of electricity,conductor of heat

• Made from clay. • High melting point. • Hard but fragile. • Does not corrode. • Poor conductor of electricity. • Can be moulded into shapes.

Properties of Metals-conductor of electricity and heat

• Shiny. • Can be bent without breaking. • Can be moulded into shapes. • Good conductor of electricity. • Good conductor of heat.

Properties of Glass

- melting point, conductor/insulator, conductor of heat

• Transparent. • High melting point. • Fragile. • Can be moulded into shapes. • Poor conductor of electricity. • Poor conductor of heat.

Properties of Plastics - melting point, conductor of electricity, conductor of heat

• Lightweight. • Low melting point. • Does not corrode. • Can be moulded into shapes. • Poor conductor of electricity. • Poor conductor of heat.

Properties of Fibres- conductor of heat , conductor of electricity

• Can be spun into threads and woven into fabrics. • Able to absorb dyes. • Poor conductor of electricity. • Poor conductor of heat.

What are physical properties?

• Qualities that can be observed and measured without changing the material's composition.

Electrical Conductivity

• The measure of how easily an electric current flows through a material.

Thermal conductivity

• The measure of how easily heat flows through a material.

Melting point

• The temperature at which a material changes from a solid to a liquid state.

Boiling point

• The temperature at which a material changes from a liquid to a gas state.

Strength

• The ability of a material to support a heavy load without changing its shape permanently.

Hardness

• The resistance of a material to wear, tear, and scratches.

Flexibility

• The ability of a material to bend without breaking.

Density

• The mass of an object in proportion to its volume. • Formula: Density = Mass ÷ Volume (g/cm³).