1. Properties of Materials
Unit 4 – Materials
Technologies 1st ESO – IES Poeta Julián Andúgar
Antonio Ruiz Hernández

2. Material Properties How can we choose what material should we use?
Physical Properties
Chemical Properties
Ecological Properties

3. Physical Properties How they react to external stimuli?
Electrical
Thermal
Acoustic
Magnetic
Optical
Mechanical
Other properties

4. Electrical Properties
We can distinguish between:
Electrical conductivity: metals.
Electrical insulation: plastic, wood, stone, ceramics

5. 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.

6. Thermal Properties

7. Thermal Properties

8. Thermal Properties

9. Acoustic Properties Can you hear sound through a material?
Acoustic conductors.
Acoustic insulators: glass, cork & plastics

10. Magnetic Properties Does a magnet attract the material?
Magnetism: Ferrous metals (steel).

11. 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.

12. Optical Properties
Opaque
Transparent
Translucent

13. 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

14. 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.

15. 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.

16. 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,…)

17. Thank you very much for your attention!