Where do materials come from, and in what standard forms are they supplied?
The sources, origins and primary processing of materials (timber seasoning and conversion, metal extraction, polymerisation of crude oil, fibre sources) and the standard stock forms in which they are bought.
A focused answer to WJEC A-Level Design and Technology Unit 1 sources and origins of materials, covering where timbers, metals, polymers and fibres come from, the primary processing each undergoes (seasoning, smelting, polymerisation), and the standard stock forms in which materials are supplied.
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What this dot point is asking
WJEC wants you to know where the four main material families come from, the primary processing that turns a raw resource into usable stock, and the standard forms in which a designer actually buys the material. This matters for two reasons the exam tests: primary processing explains many properties and defects (why timber warps, why steel rusts), and stock forms drive design decisions and waste (you design around the sheet sizes and sections you can buy).
The answer
Timber: from tree to plank
Timber is felled, then converted by sawing the log into boards (through-and-through or quarter sawn, which resists warping but wastes more), and seasoned by air drying (cheap, slow) or kiln drying (fast, precise moisture control). Unseasoned timber shrinks and warps in service, so seasoning is essential.
Metals: from ore to ingot
Most metals occur as ores (metal compounds in rock) and must be extracted. Iron is reduced from iron ore in a blast furnace to make iron, then refined into steel by removing carbon. Aluminium is extracted from bauxite by electrolysis, which is very energy-intensive (a key reason recycling aluminium saves so much energy). The refined metal is cast into ingots and then rolled, drawn or extruded into stock forms.
Polymers: from crude oil to granule
Some polymers are now made from renewable sources (bioplastics such as PLA from corn starch), which WJEC links to sustainability.
Fibres and textiles: natural and synthetic
Textile fibres are natural - from plants (cotton from the cotton boll, linen from flax stems) or animals (wool from sheep, silk from the silkworm) - or synthetic, made from oil-based polymers (polyester, nylon, elastane). Fibres are spun into yarn, then woven, knitted or bonded into fabric.
Standard stock forms
Materials are supplied in standard, repeatable forms so they are predictable and economical:
- Timber and boards - planks, planed square edge (PSE) sections, dowels, sheets of MDF and plywood in standard sizes.
- Metals - sheet and plate, bar (round, square, flat, hexagonal), rod, tube, angle, channel and I-section, and wire.
- Polymers - sheet and film, rod, tube, granules and powder.
- Papers and boards - standard A-series sheet sizes and rolls, specified by gsm or thickness.
Examples in context
Example 1. An extruded aluminium window frame. Aluminium is extracted by electrolysis, then heated and forced through a die to extrude a complex constant cross-section in one operation. The stock form (the extruded section) is designed so the same profile serves the whole frame, which is efficient and explains why aluminium framing is so common.
Example 2. A flat-pack shelf in MDF. MDF is a manufactured board made from wood fibres and resin, supplied in large flat sheets. Designing the shelf parts to nest efficiently on a standard sheet minimises offcuts, a direct consequence of working with the stock form.
Try this
Q1. State two named methods of seasoning timber and give one advantage of each. [4 marks]
- Cue. Air drying - cheap, low energy; kiln drying - fast and gives precise, controllable moisture content.
Q2. Name three standard stock forms in which mild steel is supplied. [3 marks]
- Cue. Sheet or plate, round or square bar, tube, angle, channel, wire (any three).
Exam-style practice questions
Practice questions written in the style of WJEC exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
WJEC 20194 marksExplain why freshly felled timber must be seasoned before it is used to make furniture.Show worked answer →
Freshly felled (green) timber holds a large amount of moisture in its cells, often more than half its weight. Seasoning reduces this moisture content to a level in balance with the air where the timber will be used, typically around 8 to 12 per cent for indoor furniture.
If unseasoned timber were used, it would continue to dry in service and shrink unevenly, causing warping, splitting, cupping and open joints, and it would be prone to fungal decay. Seasoning also makes the timber lighter, stronger, stiffer and able to hold glue, stains and finishes properly.
Seasoning is done by air drying (stacking with spacer sticks so air circulates, which is slow and cheap) or kiln drying (a controlled heated chamber, which is fast and gives a precise moisture content). Markers reward the moisture-content reason, at least two named defects avoided, and a named seasoning method.
WJEC 20214 marksDescribe how the raw material for most polymers is obtained and converted into a usable plastic.Show worked answer →
Most polymers are derived from crude oil, a finite fossil resource. Crude oil is separated by fractional distillation in a refinery into fractions of different boiling points. The naphtha fraction is the feedstock for plastics.
Naphtha is broken into smaller, reactive molecules called monomers (such as ethene and propene) by cracking. These monomers are then joined into long chains in a reaction called polymerisation, producing polymers such as polythene and polypropylene, which are supplied as granules or powder for moulding.
Markers reward the crude-oil origin, fractional distillation and the naphtha fraction, cracking to monomers, and polymerisation to long-chain polymers. Naming a finished polymer and the supplied form (granules) gains further credit.
Related dot points
- Classification of papers and boards, timbers, metals, polymers and textiles into families, and the criteria used to select a material for a given product and context.
A focused answer to WJEC A-Level Design and Technology Unit 1 classification and selection of materials, covering the main material families (papers and boards, timbers, metals, polymers and textiles), how each splits into sub-groups, and the criteria used to justify a material choice for a product.
- Physical and mechanical working properties of materials - strength, hardness, toughness, ductility, malleability, elasticity, plasticity, density, durability, electrical and thermal conductivity - and how they govern selection and processing.
A focused answer to WJEC A-Level Design and Technology Unit 1 working properties of materials, covering the physical properties (density, conductivity, durability) and mechanical properties (strength, hardness, toughness, ductility, malleability, elasticity, plasticity) and how each affects material selection and processing.
- The main categories of manufacturing process - wasting, shaping by casting and moulding, deforming and reforming, fabrication and joining - and how the chosen process depends on material, form and scale.
A focused answer to WJEC A-Level Design and Technology Unit 1 manufacturing processes, covering wasting, casting and moulding, deforming and reforming, fabrication and joining, with named processes such as injection moulding, vacuum forming, casting, turning and laminating, and how process choice depends on material and scale of production.
- The 6 Rs (rethink, refuse, reduce, reuse, repair, recycle) and the ecological and social footprint of products, including finite and non-finite resources and responsible material sourcing.
A focused answer to WJEC A-Level Design and Technology Unit 1 sustainability, covering the 6 Rs (rethink, refuse, reduce, reuse, repair, recycle), finite and non-finite resources, the ecological and social footprint of products, and responsible sourcing such as FSC timber.
- The reasons for applying surface treatments and finishes (protection, durability, aesthetics, hygiene) and named finishes for timber, metal and polymer such as varnish, paint, galvanising, anodising, powder coating and self-finishing.
A focused answer to WJEC A-Level Design and Technology Unit 1 surface treatments and finishes, covering why finishes are applied (protection, durability, aesthetics, hygiene) and named finishes for timber (varnish, stain, oil), metal (galvanising, anodising, powder coating, electroplating) and polymers (self-finishing).
Sources & how we know this
- WJEC AS/A Level Design and Technology specification — WJEC (2017)