1. Part 2: Types of Materials

2. Mechanical Properties of materials
Hardness: ability to resist indentation or abrasion
Elasticity: ability to return to original shape after undergoing a constraint
Resilience: ability to resist shock without breaking
Ductility: ability to be stretched without breaking
Malleability: ability to be flattened or bent without breaking
Stiffness: ability to retain shape when subjected to various constraints

3. Wood Wood → material from trees Two Types
Hard wood → high hardness; comes from deciduous trees (i.e. maple)
Soft wood → low hardness; comes from conifer trees (i.e. pine)
Mechanical properties of wood
Vary with
Tree species
Speed of Growth (dependent on environmental conditions) and Injuries
Water content of the wood

4. Types of Wood
Hardwood
Softwood

5. Wood Other properties of wood
Hardness, Elasticity, Resilience and Toughness
Low Thermal and Electrical Conductivity
Ease it can be shaped
Colour and Shades
Lightness

6. Modified Wood
Is treated wood or a material made from wood mixed with other substances
Made by gluing together pieces, sheets or residue of wood left over after timber harvesting
Properties of modified wood more consistent than regular wood
Examples
Plywood, Particleboard, Fibreboard

7. Types of Modified Wood
Particleboard
Plywood

8. Metals and Alloys Material extracted from mineral ore Properties:
Shiny
Malleable
Ductile
Good electrical conductivity
Mixture of a metal with one or more other substances
These other substances can be metallic or non-metallic
Two types
Ferrous Alloy (main component is iron)
Nonferrous Alloy (main component something else than iron)

9. Plastics Made from fossil fuels
Monomers are extracted and arranged in chains to form polymers
Plastics → made from polymers which other substances can be added to, to get specific properties
Are poor conductors of heat and electricity

10. Two Categories of Plastics
Thermoplastics
Thermosetting Plastics
Plastic that becomes soft enough when heated to be molded/remolded and that hardens enough when cooled
¾ of plastics produced in the world
Some are recyclable (need to have sign)
Plastic that remains permanently hard (even when heated)
Melamine; polyesters
Harder and more resilient than thermoplastics
Not recyclable in Quebec