Homework Check pp. 197-198
Ch. 12: PROPERTIES Mechanical Properties Other Properties Degradation and Protection
Copy the following definitions Text / Work Books Text Book – p. 388 Work Book - p. 199 Copy the following definitions
MECHANICAL PROPERTIES How a material reacts when subjected to one or more contraints (p. 388)
DEGRADATION OF A MATERIAL The decline in some of its properties due to the effects of the surrounding environment.
PROTECTION OF A MATERIAL the application of procedures that prevent or delay its degradation.
p. 388
HARDNESS Ability to resist indentation or abrasion
Elasticity Ability to return to original shape after undergoing a constraint.
RESILIENCE Ability to resist shocks without breaking
DUCTILITY Ability to be stretched without breaking
MALLEABILITY Ability to be flattened or bent without breaking.
STIFFNESS Ability to retain their shapes when subjected to various constraints
p. 389
RESISTANCE TO CORROSION Ability to resist the effects of corrosive substances (water, salts, etc.), which cause the formation of rust or decay.
ELECTRICAL CONDUCTIVITY Ability to carry an electric current
THERMAL CONDUCTIVITY Ability to transmit heat vs.
Categories of materials and their properties
WOOD Is a material obtained by harvesting and processing trees (wkbk p. 201)
MODIFIED WOOD Is treated wood or a material made from wood mixed with other substances
Properties
SPECIES OF TREES HARDWOOD SOFT WOOD
HARDNESS, ELASTICITY, RESILIENCE & TOUGHNESS
LOW THERMAL & ELECTRICAL CONDUCTIVITY
EASY TO SHAPE & ASSEMBLE
COLOURS & SHADES
LIGHT or HEAVY
Degradation Microorganism Fungi Insects
Pine Beetle
PROTECTION PRESSURE TREATING ROASTING
A CERAMIC Is a solid material obtained by heating inorganic matter containing various compounds, usually oxides.
Properties
LOW ELECTRICAL CONDUCTIVITY
HIGH DEGREE OF HARDNESS
LOW THERMAL CONDUCTIVITY
RESISTANT TO CORROSION
METALS & ALLOYS:
A METAL Is a material extracted from a mineral ore.
AN ALLOY Is a mixture of a metal with one or more other substances.
Properties
Good thermal and electrical conductivity
Ductile
Malleable
Degradation
OXIDATION = Corrosion = Rust
Protection
COATINGS Chrome Enamel Galvanize using a protective layer of zinc
STEEL HEAT TREATMENTS (pg 201) Are methods of enhancing certain mechanical properties of steel through periods of heating.
PLASTICS Are materials made of polymers, to which other substances may be added to obtain certain desirable properties (p. 205) Developed from FOSSIL FUELS such as petroleum and natural gas
A THERMOPLASTIC Is a plastic that becomes soft enough when heated to be molded or remolded and that hardens enough when cooled to hold its shape
A THERMOSETTING PLASTIC Is a plastic that remains permanently hard, even when heated
A COMPOSITE Is formed by combining materials from different categories to obtain a material with enhanced properties.
Carbon Fiber
Homework Work Book - p. 199-208