1. MATERIALS

2. Class contents:
1. MATERIALS AND RAW MATERIALS
2. PROPERTIES OF MATERIALS
3. CHOICE OF MATERIALS

3. TECHNICAL PRODUCTS are made with TECHNICAL
MATERIALS that are obtained from RAW MATERIALS.
Example: The production of a sweater.
RAW MATERIAL TECHNICAL MATERIAL TECHNOLOGICAL
PRODUCT

4. 1. Materials and raw materials
Raw materials:
Substances that are extracted directly from nature and are
transformed through physical and chemical processes into
technological products.
Raw materials that have been manufactured but still are not a
commodity are considered technical materials or materials.
ANIMALS
TYPES PLANTS
MINERALS

5. Technical Materials
Those materials that are used directly in the production of
technological products. They are obtained from raw materials.
Among the most highly used materials:
a) Wood: Obtained from the woody part of trees.
It is used as a combustible, for making paper, furniture, construction
and decorative elements, etc.
b) Plastics: Obtained artificially from oil. Plastics are used to make tubes,
toys, recepticles, electrical insulators, etc.
c) Metals: Extracted from minerals that form rocks. Metals are used for
structures and pieces of equipment, tools, welding, electronic
components, furniture, etc.

6. d) Stone (including ceramics and glass). Extracted from rocks. Some
examples are marble, chalkboard, plaster, cement, and concrete.
Normally, these are used as construction materials.
e) Textiles. These materials are used in the form of string to make
cloth/fabric. They can be natural or synthetic. Examples are wool, cotton,
silk, nylon, etc.
f) Composite materials and alloys. Sometimes we want to combine the
properties of various materials into one. For those, we use composite
materials. For example: red-brick, plywood, fiber-glass.
Normally, metals are not used in pure state. Instead, they are mixed
with other metals to form alloys. Examples are bronze, brass and steel.

7. 2. Properties of materials
Each material has their own properties:
a) This differentiates them from the
rest.
b) Determines their use.
2.1. Physical properties
2.2. Mechanical properties
2.3. Chemical properties
2.4. Ecologic properties

8. 2.1. Physical properties:
Physical properties indicate how a material is and how it behaves
when exposed to external stimuli like light, heat or electricity.
a) Density
b) Electrical, thermal or acoustic conductivity
c) Optical properties
d) Porosity

9. a) Density:
The relation between the mass of a material and its volume.

10. b) Electrical, thermal and acoustic conductivity:
The ability of materials to transmit or block electrical current,
heat or sound. Insulators do not allow these to pass and
conductors do allow them to pass.
Thermal conductivity is associated with expansion and
contraction (ability of materials to expand or contract their
volume along with the temperature). Fusibility is when some
materials change from solid to liquid when their temperature
is increased.

11. c) Optical properties.
Material’s ability to permit light are classified into:
transparent, translucent, and opaque.
d) Porosity.
Some materials can absorb or release liquids or gases. Wood
and ceramic materials are porous (they contain tiny holes called
pores).

12. 2.2. Mechanical properties:
Related to the behavior of material when external forces are
applied:
a) Hardness
b) Toughness / Brittleness
c) Maleability
d) Ductility
e) Elasticity
f) Plasticity
g) Mechanical resistence

13. a) Hardness:
Resistence of a material
from being scratched
Mohs’ scale:
10 diamond - 1 talc (less
hard).

14. b) Toughness/brittleness:
The resistance to breaking that a material shows when hit by
something. Brittleness is when a material breaks easily.
tough brittle

15. c) Malleability:
Allows a material to be spread into sheets.
d) Ductility:
Allows a material to be formed into filaments or wires.
Slate Copper - tin

16. e) Elasticity:
The property of material to return to their
original form when the deforming force
stops.
f) Plasticity:
The property of a material to deform
permanently when a deforming force
stops.

17. g) Mechanical resistance:
The property of materials to withstand forces without breaking.
The forces can be from tension, compression, bending,
severing/shearing or torsion.
Bending Tension - traction
Compression Torsion

18. 2.3. Chemical properties:
Oxidation and corrosion:
This happens when a mineral reacts with oxygen in the air or
water. The reddish-brown substance produced is called rust.

19. 2.4. Ecological properties:
Those properties related to the harmfulness of materials to the
environment.
a) Recyclability: The ability to reuse materials.
b) Biodegrability: The ability of materials to naturally decompose
over time into simpler substances.
c) Toxicity: The harmful nature of materials to the environment or
human beings.

20. More than 4,000 years
to decompose
More than 100
20 days to decompose years to
decompose

21. 3. Selection of materials
To choose a material, you must take into account certain factors:
a) Price.
b) Its properties: Resistance, hardness, flexibility,
conductivity, etc…
c) Production possibilities: the machines and tools that you
can use and the ease of the work…
d) Its ease of obtaining: the abundance of the material, its
proximity to where it is needed…
e) Its impact on the natural environment: if it pollutes, if it
is biodegradable, etc…

22. Examples.
a) Elasticity?
b) Thermal conductivity?

23. So...
Why are we going to use these Which materials are you going to
materials for your robot? use to design the costume of
your INSECT-robot?

24. Documentación original (Propiedades y materiales.pdf en tecnodesvanprimeroeso) preparada por:
•Jesús Álvarez
Adaptada y traducida por:
•Kostyn Tyksinski
•Rosa Fernández