materials and their working properties

• What is the relationship between A3 and A4 paper sizes?

  A3 is twice the size of A4.
• What happens when a sheet of paper is folded in half?

  It becomes the next size below.
• How is the thickness of paper measured?

  In grams per square metre (gsm).
• What weight classifies paper as board?

  Weight greater than 170 gsm.
• How is the thickness of board measured?

  In microns (µm).
• What is a micron?

  One-thousandth of a millimetre.
• What are the common types of paper and their properties?

  • Layout paper: Smooth, 50 gsm, for sketching.
  • Tracing paper: Thin, 40 gsm, transparent for copying.
  • Copier paper: 80 gsm, for printing and photocopying.
  • Cartridge paper: 80-140 gsm, textured for drawing.
• What is virgin fibre paper made from?

  Made from new wood pulp.
• What happens to paper fibers each time paper is recycled?

  They get shorter and weaker.
• What is the composition of recycled paper?

  Mixture of virgin pulp and recycled pulp.
• What are the properties and uses of card and cardboard?

  • Card: 180-300 gsm, used for greetings cards.
  • Cardboard: 300 microns+, used for packaging.
  • Folding boxboard: Rigid, used for frozen foods.
  • Corrugated cardboard: Lightweight, used for fragile items.
• What is the purpose of laminating paper?

  To improve strength and resistance.
• What are the two types of timber stock forms?

  Planks and boards.
• What are the characteristics of hardwoods?

  Close grain, harder, more expensive.
• What are the characteristics of softwoods?

  Open grain, less dense, quicker growing.
• What are the differences between laminated and compressed boards?

  • Laminated boards: Glued sheets or veneers together.
  • Compressed boards: Glued particles under pressure.
• What is the purpose of finishes on timber?

  To protect and enhance appearance.
• What is the main property of ferrous metals?

  They contain iron.
• What is the most widely used ferrous metal?

  Steel.
• What happens to ferrous metals when exposed to moisture?

  They are prone to corrosion.
• What is a non-ferrous metal?

  A metal that does not contain iron.
• Why is aluminium considered a sustainable metal?

  It takes less energy to recycle.
• What are the properties and uses of common alloys?

  • Stainless steel: Hard, corrosion-resistant, used in surgical equipment.
  • Brass: Lustrous, low friction, used in locks.
  • Bronze: Corrosion-resistant, used in coins and propellers.
• What is the purpose of finishes on non-ferrous metals?

  To prevent discolouration from oxidisation.
• What are the characteristics of thermosetting polymers?

  They cannot be reshaped once set.
• What are the characteristics of thermoplastics?

  They can be reshaped when heated.
• What are the properties used to identify polymers?

  • Weight
  • Hardness
  • Elasticity
  • Conductivity/insulation
  • Toughness
  • Strength
  • Mouldability
• Why do ferrous metals require a finish?

  To prevent them from rusting
• What are some finishes that can be applied to ferrous metals?

  Painted, plated, galvanised, powder coated
• What defines non-ferrous metals?

  They do not contain iron
• What is an alloy?

  A mixture of two or more metals
• How do non-ferrous metals react to oxidisation?

  They do not rust but discolour
• What finishes can be used for non-ferrous metals?

  Chrome plating, anodising, clear lacquer
• What can polymers be used for?

  To improve product performance and replace materials
• How can polymers be identified?

  By weight, hardness, elasticity, conductivity
• What is the primary source of most synthetic polymers?

  Crude oil, an unsustainable resource
• What are biopolymers?

  Natural polymers from renewable sources
• What is the most common biopolymer?

  Polylactate acid (PLA)
• What are the stock forms of polymers?

  Sheet, film, rod, granules, powder, tube
• What happens to thermoforming polymers when heated?

  They soften and can be moulded