This document discusses the properties of materials that should be considered when selecting materials for different uses. It outlines physical properties like electrical, thermal, acoustic, magnetic, optical, and mechanical properties. Electrical properties determine whether a material is a conductor or insulator. Thermal properties indicate how materials conduct or insulate heat. Acoustic properties show if sound can pass through. Magnetic properties reveal if a material is attracted to magnets. Optical properties define if light can pass through and if objects are visible. Mechanical properties concern strength, elasticity, plasticity, malleability, and ductility. Other discussed properties include density, permeability, and impermeability. Chemical properties change the material's composition through interactions. Ecological properties

1. Properties of Materials
AICLE Unit – Materials & Tools
Technology 2nd ESO
Javier Guerra Jiménez

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?
 Physical Properties:
 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
Translucent
Transparent

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!