CIE iGCSE Co-ordinated Sciences-C9.2 Uses of metals- Study Notes- New Syllabus
CIE iGCSE Co-ordinated Sciences-C9.2 Uses of metals – Study Notes
CIE iGCSE Co-ordinated Sciences-C9.2 Uses of metals – Study Notes -CIE iGCSE Co-ordinated Sciences – per latest Syllabus.
Key Concepts:
CIE iGCSE Co-Ordinated Sciences-Concise Summary Notes- All Topics
Uses of Metals Based on Physical Properties
Metals are chosen for specific applications due to their characteristic physical properties such as density, electrical conductivity, ductility, and resistance to corrosion. Understanding these properties helps explain why certain metals are preferred in engineering, construction, and everyday products.
- Aluminium in the manufacture of aircraft: Aluminium is lightweight due to its low density (about 2.7 g/cm³, much lower than iron at 7.87 g/cm³). This reduces the overall weight of aircraft, improving fuel efficiency and allowing the aircraft to carry more payload. Its combination of lightness, strength, and resistance to corrosion makes it ideal for structural components like fuselage and wings.
- Aluminium in overhead electrical cables: Aluminium’s low density reduces the weight of long-distance overhead power cables, making them easier to install and support. It also has good electrical conductivity, allowing electricity to flow efficiently over long distances. Its corrosion resistance ensures the cables remain durable outdoors, even in harsh weather.
- Aluminium in food containers: Aluminium is chemically resistant due to the formation of a protective oxide layer on its surface. This prevents reactions with acidic or alkaline food and drink, making it safe for storage. It is also lightweight, easy to form into cans and foils, and recyclable, making it economical and environmentally friendly.
- Copper in electrical wiring: Copper has excellent electrical conductivity, second only to silver, allowing electricity to pass with minimal energy loss. It is also ductile and malleable, meaning it can be drawn into thin wires without breaking. Its resistance to corrosion ensures long-term durability in household wiring, industrial cables, and electronics.
Example
Explain why aluminium is preferred for aircraft bodies rather than iron.
▶️Answer/Explanation
Aluminium is much lighter than iron, reducing the total weight of the aircraft. Lower weight improves fuel efficiency and allows higher payloads. Aluminium also resists corrosion and is strong enough for structural applications, whereas iron is heavier and prone to rust, making it less suitable.
Example
Why is copper chosen for household electrical wiring?
▶️Answer/Explanation
Copper allows electricity to flow with minimal resistance due to its high electrical conductivity. Its ductility permits the wires to be bent or drawn into long cables without breaking. Copper also resists corrosion, ensuring that wiring remains safe and durable over many years.
Example
Explain why aluminium is used in food cans instead of steel.
▶️Answer/Explanation
Aluminium forms a protective oxide layer that prevents corrosion and reaction with food, whereas steel can rust unless coated. Aluminium is also lighter, easier to shape into cans and foils, and recyclable, making it more suitable for food packaging than steel.