Properties of Materials
AICLE Unit – Materials & Tools
Technology 2nd ESO
Javier Guerra Jiménez
How can we choose what material
should we use?
How they react to external stimuli?
We can distinguish between:
Electrical conductivity: metals.
Electrical insulation: plastic, wood,
How do materials behave when
Thermal conductors: metals
Thermal insulators: wood and plastic
Fusibility: Metals, some plastics and
Welding: Metals, e.g. Tin.
Can you hear sound through a
Acoustic insulators: glass, cork &
Does a magnet attract the material?
Magnetism: Ferrous metals (steel).
Can you see light through a
Opaque: Light don’t pass. Wood &
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 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
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
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
Recyclable materials. They can be
reused (Glass, paper, cardboard, metal,
Toxic materials. Harmful and sometimes
poisonous (Mercury, heavy metals,
Biodegradable materials. They
decompose naturally and don’t damage
the environment (paper, bioplastics,…)