Materials

Question 1

Oak

Answer 1

Hardwood
Properties: hard, tough, durable, high density
Uses: furniture, boats, veneers
\+ Finishes well
- Contains acid which corrodes steel

Question 2

Mahogany

Answer 2

Hardwood
Properties: durable, medium density
Uses: indoor furniture + woodwork, window frames, veneers
\+ Finishes well
\+ Easy to work
- Prone to warping

Question 3

Beech

Answer 3

Hardwood
Properties: hard, tough
Uses: workshop benches, toys, furniture, kitchen worktops
\+ Turns well
\+ Finishes well
- Prone to warping

Question 4

Ash

Answer 4

Hardwood
Properties: tough, flexible, good elasticity
Uses: sports equipment, tool handles
\+ Flexible
- Can become splintered

Question 5

Pine

Answer 5

Softwood
Properties: lightweight
Uses: construction, floorboards, toys, decking
\+ Grows fast
\+ Nice colour
- Prone to warping
- Knots can fall out and leave holes

Question 6

Plywood

Answer 6

Properties: very strong in all directions, resistant to splitting
+ Available in large sheets
+ Doesn’t warp or twist
- Thin sheets are flexible and can warp if unsupported

Question 7

Chipboard

Answer 7

Structure: waste products bonded using resins. No grain.
Properties: strong in all directions, not very water-resistant
+ Uses waste materials
- Soaks up water
- Edges chip and flake if unprotected

Question 8

MDF

Answer 8

Properties: very dense, not affected by humidity (stability)
+ Thin sheets can be formed into 2D shapes
- Soaks up water

Question 9

Hardboard

Answer 9

Properties: side smooth, underside textured
Sructure: fibres soaked in resin and compressed
+ Cheap
- No grain so not very strong

Question 10

Manufactured boards

Answer 10

+ Dimensional stability
+ Can be painted or have veneers added
+ MDF, chipboard and hardboard can be made from waste

• Sharp tools needed
• Thin sheets bow if unsupported
• Edges must be sealed concealed
• Cutting and sanding creates hazardous particles

Question 11

Mild steel

Answer 11

Properties: tough, malleable, magnetic
\+ Cheap
\+ Recyclable
\+ Easy to work and join
- Will oxidise if unprotected
- Can only be case-hardened

Question 12

Stainless steel

Answer 12

Properties: hard, tough, excellent corrosion resistance
\+ Easily cleaned
\+ Doesn't need finishing
\+ Recyclable
\+ High-lustre
- Hard to use and join
- Specialist welding equipment needed

Question 13

Carbon steel

Answer 13

Properties: ductile
+ Recyclable
- Will oxidise if unprotected

Question 14

Aluminium

Answer 14

Properties: lightweight, soft, ductile, malleable, conductive, corrosion resistance
\+ Recyclable
\+ Easily cast
\+ Ductile
- Expensive
- Specialist welding equipment required

Question 15

Copper

Answer 15

Properties: malleable, ductile, good conductor, corrosion resistant
\+ Ductile
\+ Easily soldered
\+ Recyclable
- Will tarnish
- Expensive

Question 16

Zinc

Answer 16

Properties: excellent corrosion resistance
+ Recyclable
- Brittle

Question 17

Brass

Answer 17

Properties: corrosion resistant, casts well, good conductor
Composition: 65% copper, 35% zinc
+ Can be polished to a high-lustre finish
+ Tougher than copper
+ Recyclable
+ Easily cast and turned
- Expensive

Question 18

Acrylic

Answer 18

Thermoplastic
Properties: lightweight, good electrical insulator, durable
\+ Recyclable
\+ Finishes well
\+ Available in many colours
- Soft, scratches easily
- Poor chemical resistance

Question 19

Polyethene

Answer 19

Thermoplastic
Properties: tough, chemically resistant, lightweight, electrical insulator, hard, tough, waterproof, durable
\+ Recyclable
\+ Cheap
- Expensive to recycle
- Dangerous fumes released when burnt

Question 20

High-impact polystyrene

Answer 20

Thermoplastic
Properties: tough, high impact strength, electrical insulator
\+ Many colours
\+ Can be machined and painted
\+ Recyclable
- Expensive
- Will not biodegrade

Question 21

ABS

Answer 21

Thermoplastic
Properties: tough, high impact strength, lightweight, durable, scratch-resistant, electrical insulator, chemical resistance
+ Many colours
- Expensive

Question 22

Polyester resin

Answer 22

Thermosetting plastic
Properties: electrical insulator, hard, brittle, heat and chemical resistance
\+ Many colours
\+ Water resistant
- Contracts on curing

Question 23

Urea formaldehyde

Answer 23

Thermosetting plastic
Properties: stiff, hard, brittle, high tensile strength
\+ Can be coloured
\+ Very hard
- Toxic fumes given off when curing

Question 24

Carbon fibre

Answer 24

Properties: lightweight, high tensile strength
Structure: fibres of carbon in a matrix (often epoxy resin)
+ High strength-to-weight ratio
+ High tensile strength
+ Can be woven in pretty patterns
- Very expensive
- Weak in compression and impact

Question 25

Glass-reinforced plastic

Answer 25

Properties: high tensile and compressive strength, lightweight, durable
Structure: glass fibres in a matrix (polyester or epoxy resin)
\+ Lightweight
\+ Low maintenance
\+ Can be formed into any shape
\+ Good strength-to-weight ratio
\+ Surface textures can be moulded
\+ Durable
\+ UV and sea salt resistance
- Hard to repair
- Time-consuming and labour-intensive to make
- Needs a mould
- Cutting produces harmful dust

Question 26

Shape memory alloys

Answer 26

Properties: return to original shape when heated
Uses: glasses, braces, anti-scalding valves
+ Good elasticity and tensile strength
+ Lightweight
- Expensive

Question 27

Photochromic paint

Answer 27

Properties: reversibly changes colour when in UV light
Uses: clothing, vehicles, textiles
- Amount of change depends on level of UV
- Ability decays over time

Question 28

Reactive glass

Answer 28

Properties: changes colour in UV light or if voltage applied
Uses: transition lenses in glasses, windows
+ Replaces need for separate sunglasses (transition lenses)
- Expensive
- Windows are expensive to install

Question 29

Carbon nanotubes

Answer 29

Uses: harden paint, strengthen plastics, conductor, medicine
\+ Tensile strength
\+ Electrical conductor
\+ Tough
\+ Chemically inert
- Expensive
- Toxic