It takes 20 days to

be descomposed

It takes more

than 100 years

It takes more

than 4000 years

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…

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 anumbrella with paper because whenit rains, the umbrella would break down.

Materials properties are a

set of characteristics which

define each material and

distinguish it from others.

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

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

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 anmetals are opaque materials

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.

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.

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 lessdense it is.

Wood, some stones and ceramic materials are porous

sponge

cork

Hard materials can scratch softermaterials.

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

clayglasslead

The harder the

material, the less

deep the

scratch.

The bell´s material doesn´tbreak when it is hitted. It´sTENACIOUS

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 easilywhen it is hitted. It´sFRAGILE.

The rubber band´s material returns to itsoriginal shape and size when we stop stretchingit. 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

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

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´smaterial doesn´tdeform excessivelywhen you catch it.

Weldability is the property of

materials that allows them to be

welded

WELDABILITY

Steels and plastics have a high

degree of weldability.

Industrial welding

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 thepossibility to be poured into moulds.

Iron, 1184ºC Copper, 1084ºC Lead, 327ºC Gallium, 30ªC Water, 0ºC

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.

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

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.

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.