Keys Cambridge English for Engineering Teachers Notes

UNIT 2 Materials technology Teacher’s Notes

c Students complete the task in pairs.

Suggested answers

In tyres, puncture and tear resistance help to stop punctures and

blowouts and abrasion resistance helps the tyre to last longer. In drive belts, high elasticity allows belts to fit tightly and abrasion resistance helps them resist the friction caused by the belt turning. In brake pads, abrasion resistance helps the pads to last longer and thermal stability helps them resist the heat generated during braking. Kevlar® helps make bullet-resistant armour, which is generally heavy, more lightweight, which is better for the vehicle’s performance. Kevlar® makes sealing gaskets durable and its thermal stability allows them to resist heat

– for example, in engine cylinder heads – and its chemical stability means gaskets are not affected by engine fluids such as fuel, lubricating oil and coolant liquids.

Extension activity: more vocabulary

You could look at the meaning of some of the terms in Exercise 9b in more detail. puncture (n) = hole causing a leak of air or liquid, for example in a tyre

tear /te@(r)/ resistance = resistance to tearing (a sheet of material being pulled apart)

tension = a stretching force

revolution = one turn of something, a wheel for example

lifespan = the length of time for which a person, animal or thing exists – this also describes how long mechanical components last

frictional forces = resistance when two surfaces rub together pulp = a mass of small particles or fibres, mixed together

handling = how a vehicle responds to control inputs from the driver, for example to steering, throttle and brakes when it is driven

chemical stability = resistance to damage from chemical substances

galvanic corrosion = corrosion caused when two different types of metal are in direct contact with each other

c Students match the words and phrases and the synonyms.

Answers

1   b          2   a          3   e          4   c          5   d

Before you begin …

Discuss what is meant by hand tools (= tools that are held in the hand and are not powered). Ask students to give some examples of hand tools, for example hammer, saw, screwdriver, pliers.

11a Students complete the task in pairs. b Students complete the task in pairs.

UNIT 2 Materials technology Teacher’s Notes

b Students complete the task in pairs.

Answers

1T

2T

3F – it needs a protective coating.

4F – he says it’s fairly poor in terms of looks.

5F – no – for the reasons given above.

6F – inadequate materials have never been chosen for marketing reasons.

7T

8F – complicated names are not good for marketing.

c 2.6 Students listen and underline the stressed syllable.

d Students complete the table.

Answers

1extremely, exceptionally, tremendously

2quite, fairly, pretty, relatively

3not very, not particularly, not (all) that

4not enough, insufficiently, not adequately

5definitely not, not at all

Extension activity: marketability

Ask the students to give their views on how marketable the following materials are.

steel      stainless steel      cast iron      titanium      plastic      aluminum/aluminium concrete      copper

Encourage them to use language from Exercise 14d. Since the answer depends partly on the application in question, discuss examples of products and uses where some of the materials are viewed positively by customers.

15 Students complete the task in pairs.

Suggested answers

Steel is relatively heavy and very tough. It is pretty scratch-resistant and shockresistant. Mild steel is not very corrosion-resistant but stainless steel has good corrosion resistance and is therefore suitable for watches. Glass is quite heavy and is water-resistant and corrosion-resistant. Ordinary glass is very brittle and has fairly poor shock resistance and scratch resistance, although it is still suitable for watches. Toughened glass is more durable. Aluminium is relatively lightweight and is fairly tough. It has good corrosion resistance. It is therefore suitable for watches. Titanium is exceptionally lightweight and tough and has excellent abrasion resistance. It is also extremely corrosion-resistant and is therefore an excellent watch material. Gold is extremely heavy and pretty tough, although softer grades of gold have quite poor shock resistance and scratch resistance. Gold has excellent corrosion resistance. It is suitable for more expensive, decorative watches.

UNIT 2 Materials technology Teacher’s Notes

16 Students complete the task in small groups.

Extension activity: the company’s products

If your students are in work, you could ask them to talk about the quality of their company’s products compared with those of the competition. This could include the issue of cost, and also perceived quality. Are customers’ perceptions of the company’s products accurate?

UNIT 2 Materials technology Teacher’s Notes

Background information and useful web links

Describing specific materials (pages 14 and 15)

This section focuses on commonly used engineering materials. This topic is central to all branches of engineering as any given branch of engineering uses a wide range of different materials. The context of recycling reflects the increasing importance of environmental considerations in engineering design.

Categorising materials (pages 16 and 17)

This section extends the topic of materials by looking at categories of engineering materials. The language is useful for understanding and describing the vast array of materials used in modern technology, such as conductors, insulators and semi-

conductors in electrical engineering, and composite materials and alloys in mechanical and civil engineering.

Specifying and describing properties (pages 18 and 19)

This section deals with the physical properties of materials, from the point of view of describing properties, as well as specifying what properties are required/desirable for a given application. In all fields of engineering, materials are selected for their specific properties. Specifying required properties is therefore central to engineering design.

Kevlar http://www2.dupont.com/Kevlar/en_US/

http://www2.dupont.com/Kevlar/en_US/assets/downloads/KEVLAR_Technical_Guide.pdf

Discussing quality issues (pages 20 and 21)

In dealing with the topic of quality, this section covers language for describing degree (exceptionally, not particularly, etc.) This provides a skill-based extension of the previous section, allowing the properties of materials to be qualified (exceptionally tough, not particularly durable, etc.)

Professional English

Cambridge English for

Engineering

TEACHER’S NOTES

UNIT 2 Materials technology

Resource sheet 2a

Are the sounds in bold the same or different?

Professional English

Professional English

Cambridge English for

Engineering

TEACHER’S NOTES

UNIT 2 Materials technology

Resource sheet 2c

Complete the table using the materials in the box. You will need to use each material more than once. Add any other examples you can think of.

aluminium/aluminum    bronze    copper    glass    iron    nylon    steel    synthetic rubber

Alloys

Non-metals

Ferrous metals

Non-ferrous metals

Polymers

Ceramics

Professional English

Cambridge English for

Engineering

TEACHER’S NOTES

UNIT 2 Materials technology

Resource sheet 2d

Complete the table with adjectives and nouns. Underline the stressed syllables.

5durable

6light

8flexible

9heavy

10brittle

11rigid