Unit 3

Question 1

What is a ferrous metal?

Answer 1

Contains iron, magnetic, prone to corrosion. Example: mild steel, cast iron.

Question 2

What is a non-ferrous metal?

Answer 2

Does not contain iron, not magnetic, corrosion-resistant. Example: copper, aluminium.

Question 3

What is an alloy?

Answer 3

A mixture of two or more metals (or a metal and another element) to improve properties. Example: brass = copper + zinc.

Question 4

What is a hardwood?

Answer 4

Timber from deciduous (slow-growing) trees. Denser, more expensive. Example: oak, beech, mahogany.

Question 5

What is a softwood?

Answer 5

Timber from coniferous (fast-growing) trees. Lighter, cheaper. Example: pine, spruce.

Question 6

What is a manufactured board?

Answer 6

Man-made wood-based sheet material. Example: MDF, plywood, chipboard.

Question 7

What is MDF?

Answer 7

Medium Density Fibreboard: made from wood fibres and resin, dense, smooth, but produces harmful dust when cut.

Question 8

What is plywood?

Answer 8

Layers of veneer glued together at 90° angles. Strong and stable.

Question 9

What are thermoplastics?

Answer 9

Plastics that can be melted and reshaped repeatedly. Recyclable. Example: acrylic, polyethylene.

Question 10

What are thermosetting plastics?

Answer 10

Plastics that once set, cannot be reshaped. Heat-resistant. Example: melamine, epoxy resin.

Question 11

What is toughness?

Answer 11

The ability to absorb energy without fracturing. Example: rubber.

Question 12

What is hardness?

Answer 12

Resistance to scratching, cutting, or wear. Example: glass, hardened steel.

Question 13

What is plasticity?

Answer 13

Ability of a material to permanently deform without breaking.

Question 14

What is elasticity?

Answer 14

Ability of a material to return to its original shape after deformation. Example: elastic band.

Question 15

What is brittleness?

Answer 15

Material breaks without significant deformation. Example: glass.

Question 16

What is ductility?

Answer 16

Ability to be stretched into wire. Example: copper.

Question 17

What is malleability?

Answer 17

Ability to be hammered or rolled into shape without breaking. Example: gold.

Question 18

What is conductivity (thermal and electrical)?

Answer 18

Ability to conduct heat or electricity. Metals = good conductors; plastics = poor.

Question 19

What is corrosion?

Answer 19

Degradation of materials due to reaction with environment (e.g. rust on iron).

Question 20

What is grain direction in wood?

Answer 20

The alignment of wood fibres. Cutting or bending across the grain can weaken the material.

Question 21

Name a property of oak.

Answer 21

Hard, tough, durable. Often used in furniture and flooring.

Question 22

What is beech used for?

Answer 22

Strong, hard, resists wear. Used in tools, toys, furniture.

Question 23

What are the properties of pine?

Answer 23

Lightweight, easy to work, affordable. Susceptible to knots.

Question 24

What is chipboard?

Answer 24

Made from wood chips and resin, cheap, not strong, used in flat-pack furniture.

Question 25

What is a smart material?

Answer 25

Material that responds to external stimuli (e.g. temperature, light). Example: thermochromic pigment.

Question 26

What is a modern material?

Answer 26

Material developed through new processes to perform specific functions. Example: Kevlar, carbon fibre.

Question 27

What are composites?

Answer 27

Two or more materials combined to create enhanced properties. Example: fibreglass, concrete.

Question 28

What are the disadvantages of MDF?

Answer 28

Heavy, swells with moisture, produces fine dust when cut (hazardous).

Question 29

What is carbon fibre used for?

Answer 29

Lightweight and extremely strong — used in aerospace, sports equipment.

Question 30

What is Kevlar?

Answer 30

A synthetic fibre known for extreme toughness and light weight — used in body armour.

Question 31

What is a laminated material?

Answer 31

Layers of material bonded together. Example: plywood, safety glass.

Question 32

What is the difference between strength and toughness?

Answer 32

Strength = resists force; Toughness = resists impact and shock

Question 33

What is density?

Answer 33

Mass per unit volume. Affects weight. Metals = usually high density. Plastics/woods = lower.

Question 34

Why is aluminium corrosion-resistant?

Answer 34

It forms a thin oxide layer that protects it from further corrosion.

Question 35

What property makes copper good for electrical wiring?

Answer 35

Excellent electrical conductivity and ductility.

Question 36

What is a material's working property?

Answer 36

How it behaves under specific conditions — includes strength, ductility, hardness, etc.

Question 37

Name a thermosetting plastic used in kitchenware.

Answer 37

Melamine formaldehyde — durable, heat-resistant, used for plates/cups.

Question 38

Name a thermoplastic used in bottles

Answer 38

Polyethylene terephthalate (PET) — lightweight, shatter-resistant.

Question 39

What is the environmental concern with thermosetting plastics?

Answer 39

Cannot be remelted or recycled easily — ends up in landfills or incinerators.

Question 40

What’s a key safety risk when cutting MDF?

Answer 40

Releases fine dust particles that can irritate lungs. Use a mask and ventilation.

Question 41

Why is acrylic used in school projects?

Answer 41

Easy to shape with heat, comes in many colours, good aesthetic finish

Question 42

Why is brass used in instruments?

Answer 42

Malleable, corrosion-resistant, good acoustic properties.

Question 43

What is the difference between ductility and malleability?

Answer 43

Ductility = drawn into wire; Malleability = shaped by compression

Question 44

What does the term ‘stock form’ mean?

Answer 44

The standard shape/size materials are supplied in — e.g. sheets, rods, bars.

Question 45

What is tempering in metal?

Answer 45

A heat treatment to reduce brittleness and improve toughness.

Question 46

What is case hardening?

Answer 46

Hardening the surface of low-carbon steel while keeping the core soft for toughness.

Question 47

What is annealing?

Answer 47

A heat treatment that softens metal to improve ductility and reduce hardness

Question 48

What makes stainless steel rust-resistant?

Answer 48

Chromium content forms a passive oxide layer that prevents corrosion.

Question 49

What is tensile strength?

Answer 49

The resistance to being pulled apart. High in materials like steel

Question 50

What is compressive strength?

Answer 50

The ability to withstand being squashed. Example: concrete has high compressive strength.