Materials

Question 1

What sort of plastics can only be heated once?

Answer 1

Thermosetting plastics. These plastics undergo a chemical change change when heated and become hard and rigid.

Question 2

Can thermosetting plastics be recycled?

Answer 2

No. thermosetting plastics cannot be recycled.

Question 3

What are thermosetting plastics used for, because they resist heat so well?

Answer 3

Electrical fittings and pan handles. Also, any situation when the plastic needs to be very hard.

Question 4

Examples of thermosetting plastics

Answer 4

Melamine-formaldehyde
Polyester resin
Epoxy resin
Urea-formaldehyde

Question 5

What sort of plastics do not resist heat well - they can be melted and formed multiple times?

Answer 5

Thermoplastics can be melted and formed many times. When formed, they are also very bendy.

Question 6

Are thermoplastics recyclable?

Answer 6

Yes. Thermoplastics can be melted down and reformed into a new product.

Question 7

Examples of thermoplastics?

Answer 7

Acrylic
ABS
Polystyrene
High Impact Polystyrene
Polythene

Question 8

Surface finishes for plastics?

Answer 8

Plastics don’t need protective surface finishes because they are very resist pant to corrosion and decay

Question 9

Giving a plastic surface a nice appearance.

Answer 9

Wet and dry paper (silicon carbide).
Mild abrasive polish,
Anti-static cream,
Buffing machine.

Question 10

Plastics are made from….

Answer 10

Crude oils. They are extracted from the ground then taken to a refinery. The oils are separated. Some are used to make plastics.

Question 11

Ferrous metals contain….

Answer 11

Iron. They are often magnetic.

Question 12

Properties of Mild Steel?

Answer 12

Strong and cheap. Rusts easily and can’t be hardened or tempered.

Question 13

Uses of Mild Steel?

Answer 13

Car bodies, screws, nuts, bolts, nails, washing machines.

Question 14

Properties of High-Carbon Steel?

Answer 14

Hard and can be hardened or tempered. Unfortunately, it is hard to work and rusts.

Question 15

Properties of Stainless Steel?

Answer 15

Hard and doesn’t rust but is expensive

Question 16

Uses of High-Carbon Steel?

Answer 16

Drills, files, chisels and saws

Question 17

Use of Stainless Steel?

Answer 17

Medical Equipment, Sinks, Kettles, Cutlery

Question 18

What’s a Non-Ferrous Metal?

Answer 18

Doesn’t contain iron.

Question 19

Properties of Aluminium?

Answer 19

Lightweight and corrosion resistant. Expensive and not particularly strong.

Question 20

Uses of Aluminium?

Answer 20

Aeroplanes, Cans, Ladders

Question 21

Properties of Brass?

Answer 21

Quite strong, Corrosion-Resistant, Malleable, Ductile.

Question 22

Properties of Copper?

Answer 22

Malleable, Ductile and conducts electricity well.

Question 23

Uses of Copper?

Answer 23

Wiring, Pipes

Question 24

Uses of Brass?

Answer 24

Door Handles, Electrical Parts

Question 25

Common stock forms

Answer 25

Sheet, Strip, Tubing

Question 26

2 composites?

Answer 26

Glass-reinforced plastic : boats, cars | Carbon fibre reinforced plastic : protective helmets, racing cars, bulletproof vests

Question 27

Why might nano-materials be bad?

Answer 27

Harmful to environment and difficult/expensive to dispose of

Question 28

What's a smart material?

Answer 28

A smart material are materials that react to a stimuli in their environment.

Question 29

What is annealing?

Answer 29

Metal is heated and left to cool slowly. This makes it softer, ductile and less brittle

Question 30

What is hardening?

Answer 30

Metal is heated, then cooled rapidly. Heated then put in water to cool. This leaves metal brittle, so it is often tempered afterwards.

Question 31

What is tempering?

Answer 31

Tempering makes metal tougher and less likely to break. It is done by gently heating the metal.

Question 32

Explain plastic coating.

Answer 32

Metal is heated evenly then plunged into fluidised powder for a few seconds. Metal is put back into the oven and plastic fuses to it.

Question 33

Recycling wood

Answer 33

Wood is either reclaimed or shredded to make playground flooring, chipboard or compost.

Question 34

6 R's of recycling

Answer 34

``` Repair Reuse Recycle Rethink Reduce Refuse ```