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This lesson covers the sources and origins of metals, polymers, and textiles, as required by AQA GCSE D&T (8552), Section 3.2.4. Understanding where these materials come from, how they are obtained, and the environmental and ethical issues associated with their extraction is essential for responsible design.
Metals are extracted from ores — naturally occurring rocks that contain metal compounds (usually metal oxides or sulphides). The ore must be mined, then the metal must be separated from the ore through a process called extraction or smelting.
| Metal | Ore | Extraction Method | Primary Source Countries |
|---|---|---|---|
| Iron | Haematite (iron oxide) | Blast furnace (reduction with carbon/coke) | Australia, Brazil, China, India |
| Aluminium | Bauxite (aluminium oxide) | Electrolysis (very energy-intensive) | Australia, Guinea, Brazil, Jamaica |
| Copper | Chalcopyrite (copper iron sulphide) | Smelting and electrolytic refining | Chile, Peru, China, DRC |
| Tin | Cassiterite (tin oxide) | Smelting with carbon | China, Indonesia, Myanmar |
| Zinc | Sphalerite (zinc sulphide) | Roasting and electrolysis | China, Australia, Peru |
| Gold | Native gold (free metal) or in quartz | Cyanide leaching or mercury amalgamation | China, Australia, Russia, USA |
| Category | Contains Iron? | Magnetic? | Rusts? | Examples |
|---|---|---|---|---|
| Ferrous | Yes | Yes (most) | Yes (unless protected) | Mild steel, cast iron, stainless steel, high-carbon steel |
| Non-ferrous | No | No | No (but may corrode) | Aluminium, copper, zinc, tin, gold, silver, titanium |
An alloy is a mixture of two or more metals (or a metal and a non-metal) combined to improve properties.
| Alloy | Base Metals | Key Property | Common Use |
|---|---|---|---|
| Stainless steel | Iron + chromium (+ nickel) | Corrosion-resistant | Cutlery, kitchen sinks, medical instruments |
| Brass | Copper + zinc | Attractive gold colour, easy to machine | Door handles, musical instruments, plumbing fittings |
| Bronze | Copper + tin | Hard, corrosion-resistant | Bearings, sculptures, bells |
| Duralumin | Aluminium + copper + magnesium | Strong and lightweight | Aircraft structures |
| Solder | Tin + copper (lead-free) | Low melting point | Electronic circuit board assembly |
AQA Exam Tip: Know the difference between ferrous and non-ferrous metals, and be able to give examples of each. Also know at least three common alloys, their compositions, and their uses. Alloy questions appear frequently in the exam.
Polymers (plastics) are large molecules made by joining many small molecules (monomers) together in a process called polymerisation.
The vast majority of polymers are derived from crude oil (a fossil fuel). The process is:
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