Properties of Materials Unit 4 – Materials Technologies 1st ESO – IES Poeta Julián Andúgar...
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Transcript of Properties of Materials Unit 4 – Materials Technologies 1st ESO – IES Poeta Julián Andúgar...
Properties of Materials
Unit 4 – Materials
Technologies 1st ESO – IES Poeta Julián AndúgarAntonio Ruiz Hernández
Material Properties
How can we choose what material should we use? Physical Properties Chemical Properties Ecological Properties
Physical Properties
How they react to external stimuli? Physical Properties:
Electrical Thermal Acoustic Magnetic Optical Mechanical Other properties
Electrical Properties
We can distinguish between: Electrical conductivity: metals. Electrical insulation: plastic, wood,
stone, ceramics
Thermal Properties
How do materials behave when heated? Thermal conductors: metals Thermal insulators: wood and plastic Fusibility: Metals, some plastics and
glass. Welding: Metals, e.g. Tin.
Acoustic Properties
Can you hear sound through a material? Acoustic conductors. Acoustic insulators: glass, cork &
plastics
Optical Properties
Can you see light through a material? Opaque: Light don’t pass. Wood &
Metals. Translucent: Light passes, but we
cannot see objects behind them clearly. Some types of glass and plastic.
Transparent: We can see perfectly through them: Glass and some plastics.
Mechanical Properties
Mechanical Strength. How the material resists the action of forces.
Elasticity. The material returns to its original form after a force that has changed its shape is removed.
Plasticity. The material is permanently deformed after a force is applied.
Malleability: Allows a material to be spread into sheets or films.
Ductility: Allows a material to be formed into filaments or wires
Other Physical Properties
Density. Relation between mass of an object and its volume.
Permeability: Allows water or other liquids to filter through them.
Impermeability: Doesn’t allow water or other liquids to filter through them.
Chemical Properties
When the chemical composition of a material changes because it interacts with other substances.
Oxidation. The material reacts with the oxygen in the air or water. This happens with metals, producing rust.
Ecological Properties
Recyclable materials. They can be reused (Glass, paper, cardboard, metal, plastics).
Toxic materials. Harmful and sometimes poisonous (Mercury, heavy metals, petroleum).
Biodegradable materials. They decompose naturally and don’t damage the environment (paper, bioplastics,…)