Wood comes from trees Modified wood is treated

• Wood comes from trees • Modified wood is treated wood or a material made from wood mixed with other substances. • (i. e. Plywood, particleboard, fibreboard)

Degradation/Protection of wood and modified wood • Lots of water = bad for wood • Treated wood = protected wood • 2 ways to treat wood • - Dipping it in an alkaline solution containing copper. • - Heating it to a high temperature.

Ceramics A ceramic is a solid material obtained by heating inorganic matter containing various compounds, usually oxides. (silicon dioxide) Ceramics : - Good insulators - High degree of hardness - Low thermal conductivity - Resistance to corrosion - Fragile - Some acids/bases degrade ceramics

Metals and Alloys • Metal = from mineral ore • - Good conductors of electricity and heat • An alloy = mixture of metal + one or more substances (metal or non metal)

Degradation/Protection of metals & alloys • Degradation = from corrosion (oxidation) • Protection = Coating • - Metallic coatings (zinc, gold, silver) • - Non metallic coatings (paint, grease)

Heat Treatment • To enhance metal/alloy properties • steel (alloy made from iron + carbon) • steel heat treatment • - To create harder steels using quench hardening and tempering. (3 stages) • 1) heating (high) • 2) cooling • 3)heating (low)

Plastics • Made of polymers (derived from fossil fuels) • 2 types : • - Thermoplastics (because soft when heated) • -Thermosetting (remains hard even when heated)

Degradation/Protection of plastics • - water, acids, oxidation, UV rays degrade plastics • To protect = waterproof coating, add antioxidants, add pigments that absorb UV rays

Composites • Formed by combining materials from different categories to obtain a material with enhanced properties • Plastic + fibreglass • (matrix) + reinforcement