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Material identification and comparison questions are among the most common question types on AQA GCSE D&T Paper 1. This lesson provides strategies, model answers and practice for these questions. Specification reference: AQA 8552, Sections 3.1.6, 3.2.1 and 3.2.2.
| Question Type | Example | Marks |
|---|---|---|
| Identify | "Name the type of timber shown in the photograph." | 1 |
| Select and justify | "Recommend a suitable material for the handle of a frying pan. Justify your choice." | 3–4 |
| Compare | "Compare the properties of mild steel and aluminium for use in bicycle frames." | 4–6 |
| Classify | "Classify the following materials as thermoplastic, thermosetting polymer or elastomer." | 2–3 |
| Explain properties | "Explain why carbon fibre is used for Formula 1 car bodies." | 3–4 |
| Category | Examples | Key Properties |
|---|---|---|
| Hardwoods | Oak, beech, mahogany, teak, ash, balsa | Generally harder, denser, more durable; from deciduous trees |
| Softwoods | Pine (Scots pine), spruce, cedar, larch | Generally softer, lighter, cheaper, faster-growing; from coniferous trees |
| Manufactured boards | MDF, plywood, chipboard, hardboard | Made from wood fibres/veneers; available in large sheets; no grain direction |
| Category | Examples | Key Properties |
|---|---|---|
| Ferrous (contain iron) | Mild steel, cast iron, high-speed steel, stainless steel | Magnetic (except stainless steel); prone to rust (except stainless steel) |
| Non-ferrous (no iron) | Aluminium, copper, brass, zinc, tin, silver, gold | Do not rust; not magnetic; often lighter or better conductors |
| Alloys | Stainless steel (iron + chromium + nickel), brass (copper + zinc), bronze (copper + tin), duralumin (aluminium + copper) | Combinations of metals to improve properties |
| Category | Examples | Key Property |
|---|---|---|
| Thermoplastics | ABS, acrylic (PMMA), polypropylene (PP), HDPE, PET, PVC, HIPS, nylon | Can be reheated and reshaped; recyclable |
| Thermosetting | Epoxy resin, polyester resin, melamine formaldehyde, urea formaldehyde | Set permanently when cured; cannot be reshaped; heat resistant |
| Elastomers | Natural rubber, silicone, neoprene | Can stretch and return to original shape |
AQA Exam Tip: Learn at least three specific examples for each material category. Exam questions often ask you to "name a suitable material" — generic answers like "plastic" or "metal" score zero marks. You must name the specific material (e.g. "polypropylene" or "mild steel").
Question: Recommend a suitable material for a child's outdoor playground slide surface. Justify your choice.
Answer: I would recommend HDPE (high-density polyethylene).
Always use a comparison table for compare questions. This ensures you cover both materials and directly compare equivalent properties.
Question: Compare mild steel and aluminium as materials for a bicycle frame. Recommend which is more suitable for a lightweight racing bicycle.
| Property | Mild Steel | Aluminium |
|---|---|---|
| Density | 7,850 kg/m³ — heavy | 2,700 kg/m³ — approximately 1/3 the weight of steel |
| Strength | High tensile strength (400–550 MPa) | Lower tensile strength (70–300 MPa depending on alloy) but adequate for frames |
| Corrosion resistance | Poor — rusts without a protective coating (paint, galvanising) | Good — forms a natural oxide layer; does not rust |
| Cost | Cheap and widely available | More expensive than mild steel (approximately 3× the price per kg) |
| Weldability | Easy to weld (MIG, TIG) | Requires specialised TIG welding; higher skill level needed |
| Fatigue life | Excellent — steel has a fatigue limit (endures indefinitely below a threshold) | No true fatigue limit — aluminium frames eventually fail under repeated loading |
Recommendation: For a lightweight racing bicycle, aluminium (typically 6061-T6 alloy) is more suitable because its low density (1/3 of steel) significantly reduces the frame weight, which is the priority for racing performance. Although aluminium is more expensive and has fatigue limitations, modern aluminium frames are designed with appropriate tube profiles (hydroformed, oversized) to manage stress concentrations. A steel frame would be more suitable for a touring or commuter bicycle where weight is less critical and durability is prioritised. (2)
AQA Exam Tip: A compare question MUST discuss similarities AND differences. Do not just list properties of each material separately — use comparative language: "whereas," "in contrast," "however," "both materials share."
In exam questions, you may need to identify materials from descriptions or images. Look for these clues:
| Clue | Likely Material |
|---|---|
| "Transparent" | Acrylic (PMMA), glass, polycarbonate, PET |
| "Lightweight, corrosion-resistant" | Aluminium, titanium |
| "Self-finished, glossy, moulded" | Thermoplastic (ABS, PP, polycarbonate) — injection moulded |
| "Grain pattern visible" | Natural timber (hardwood or softwood) |
| "Smooth, no grain, consistent" | MDF, plywood, or polymer |
| "Rusty" | Ferrous metal (mild steel, cast iron) — NOT stainless steel |
| "Magnetic" | Ferrous metal (iron, steel) |
| "Stretchy, returns to shape" | Elastomer (rubber, silicone, neoprene) |
| "Hard, heat-resistant, brittle, cannot be remoulded" | Thermosetting polymer (epoxy, melamine, urea formaldehyde) |
| Mistake | Correction |
|---|---|
| Saying "plastic" instead of naming the polymer | Always name the specific polymer (e.g. ABS, PP, acrylic) |
| Saying "wood" instead of naming the timber | Say "pine," "oak," "MDF," etc. |
| Confusing thermoplastic and thermosetting | Thermoplastics can be reheated and reshaped; thermosets cannot |
| Saying aluminium is a ferrous metal | Aluminium is NON-ferrous (contains no iron) |
| Confusing hardwood and softwood with hardness | Balsa is a hardwood (from a deciduous tree) but is very soft |
| Saying stainless steel does not contain iron | It DOES contain iron — it is a ferrous alloy with added chromium and nickel |
Name a suitable thermoplastic for making a transparent drinks bottle.
Answer: PET (polyethylene terephthalate).
Explain why acrylic (PMMA) is used for illuminated shop signs.
Answer:
Compare plywood and MDF for use as the back panel of a bookcase.
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