1. It takes 20 days to
be descomposed
It takes more
than 100 years
It takes more
than 4000 years
2. Technical materials are used:
To produce the objects we use in our everyday life
To construct all kinds of machines
To build houses, bridges, parks…
3. When we have to construct a object, we will choose
the material that fulfil the function for which the
object was designed.
For example, we wouldn´t make an
umbrella with paper because when
it rains, the umbrella would break
down.
Materials properties are a
set of characteristics which
define each material and
distinguish it from others.
4. Properties that define
the behaviour of
materials when they
are subjected to
atmosferic or
chemical agents
Material properties can be classified into these
groups:
Properties that define the behaviour of materials when they are
subjected to the action of physical agents such as heat,
electrical current, forces…
Physical
properties
Chemical
properties
Properties that define
the behaviour of
materials as they are
being worked
Technological
properties
5. Density is the relatioship between the mass of an object and
its volume.
Density
The piece of wood weighs more than the sponge, altough
both pieces are of a similar volume.
The wooden block has a higher density than the sponge.
𝒅𝒆𝒏𝒔𝒊𝒕𝒚 =
𝒎𝒂𝒔𝒔
𝒗𝒐𝒍𝒖𝒎𝒆
6. OPACITY is the
property of materials
that don´t allow light to
pass through them and
other objects can´t be
seen through them
OPTICAL PROPERTIES
TRANSLUCENCY is
the property of
materials that allow
light to pass through
them but don´t allow
objects behind them to
be seen clearly.
TRANSPARENCY is
the property of
materials that allow
light to pass through
them and allow objects
behind them to be
seen clearly.
Some types
of plastics or
glass are
translucent
materials
Some types
of plastics
or glass are
transparent
materials
Wood an
metals are
opaque
materials
7. Magnetism is the property of materials
that allows them to attract others metallic
materials.
MAGNETISM
The most common magnetic material is
iron.
Magnetic materials become into
permanet magnets.
8. Permeability is the property of
materials that allows water or other
liquids to filter through them.
PERMEABILITY
This earthenware is made of a
permeable material.
Glass or plastic are waterproof.
These bottles are made of
an impermeable material.
9. Porosity is the property of materials that can
absorb liquids or gases.
POROSITY
These materials contain tiny holes called
pores.
Porosity is related to density.
The more porous is a material, the less
dense it is.
Wood, some stones and
ceramic materials are
porous
sponge
cork
10. Hard materials can
scratch softer
materials.
Hardness is the property that indicates
the material´s resistance to being
scratched or penetrated.
HARDNES
S
In Science, we measure hardness
with the Moss´s scale
clay
glasslead
The harder the
material, the less
deep the
scratch.
11. The bell´s material doesn´t
break when it is hitted. It´s
TENACIOUS
Tenacity is the property of materials that
allows them to be hit or struck without
breaking.
TENACITY
Fragility is the property of
materials that don´t resist
impacts without breaking.
FRAGILITY
Ceramic breaks easily
when it is hitted. It´s
FRAGILE.
12. The rubber band´s material returns to its
original shape and size when we stop stretching
it. It is ELASTIC
Elasticity is the property of materials
that allows them to return to its original
form after a force that has changed their
shape is removed.
ELASTICITY
Plasticity is the property of
materials that don´t return to
its original form after a force
that has changed their shape
is removed.
PLASTICITY
Playdough doesn´t return to its
original shape when we stop
stretching it. It is PLASTIC
13. Ductility is the property of materials that
allows them to be formed into filaments or
wires when they are stretched.
DUCTILITY
Copper is DUCTILE
Malealibility is the property of materials
that allows them to be spread into
filaments sheets or films when they are
compressed.
MALEABILITY
Slate is MALLEABLE
14. Mechanical resistance is the property
of materials that allows them to
withstand forces without deforming
excessively or breaking
MECHANICAL
RESISTANCE
The chair´s material doesn´t
break when people sit on it.
The hammer´s material
doesn´t break when you hit
with it.
The glass´s
material doesn´t
deform excessively
when you catch it.
15. Weldability is the property of
materials that allows them to be
welded
WELDABILITY
Steels and plastics have a high
degree of weldability.
Industrial welding
16. Bronze, brass, iron…
are very fusible
materials.
Fusibility is the property of materials
that allows them to go from a solid to a
liquid state when they are subjected to
certain temperature
FUSIBILITY
Melting point is the
temperature at which a
material goes from
a solid to a liquid state.
To be very fusible materials implies the
possibility to be poured into moulds.
Iron, 1184ºC
Copper, 1084ºC
Lead, 327ºC
Gallium, 30ªC
Water, 0ºC
17. Thermal conductivity is the material´s
capacity to transmit heat.
THERMAL
CONDUCTIVITY
Metals transmit heat
easily through them, so
they are good
conductors of heat.
They are called thermal
conductors.
Wood, plastics or ceramic materials
practically prevent heat from passing
through them.
They are called thermal insulators.
The cooking pot is made of
metal, so the heat of the fire is
transmited to the food in order
to be cooked.
The handles are
made of plastic,
so we can hang
the cooking pot
without burn us.
18. Electrical conductivity is the
material´s capacity to allow an
electrical current to pass through them.
ELECTRICAL
CONDUCTIVITY
Metals are good
conductors of
electricity.
They are called
electrical
conductors.
Wood, plastics or ceramic materials aren´t
good conductors of electricity.
They are called electrical insulators or
insulators.
The tool is made of
metal because it´s
resistant enough
The handle is made of
plastic, so in case of a
electrical shock, it
doesn´t keep the
worker
19. Acoustic conductivity is the capacity
of materials to transmit sounds.
ACOUSTIC
CONDUCTIVITY
Metals are good
conductors of
sound.
They are called
acoustic
conductors.
Glass, fiber, plastics, aren´t good
conductors of sound.
They are called acoustic insulators.
The bronze
(a metal), is an
acoustic conductor.
Cotton fibers or
polyurethane are
acoustic insulators.
20. RECICLABILITY
ECOLOGICAL PROPERTIES
Paper,
water-
soluble
plastics…
Glass, paper, cardboard,
metal, plastics…
Recyclable materials
can be reused.
BIODEGRADABILITYTOXICITY
Toxic materials are
harmful to the
environment
They can be poisonous
for living as they
contamine the soil, the
water and the
atmosphere.
Biodegradable materials
are those that
descompose naturally and
don´t cause damage to the
environment.
Mercury, heavy metals,
petroleum…
They help conserve
natural resources and
avoid the accumulation of
waste products.
