Appropriate technology 31
Problem-solving
1 The Stirling engine is a simple hot air engine. Look at the diagram and put the sentences in the correct order to explain how it works.
Pairwork
Work in pairs, A and B. Study this photo of an appropriate technology device. Discuss together what it might be.
COOLED CHAMBER
a
The air cools and pressure drops in the power
cylinder.
b This displaces the air to the hot end.
с The air heats up rapidly and pushes the power piston back up the cylinder.
d This movement rotates the flywheel, drawing the displacer piston to the cold end of the cylinder.
Each of you has a diagram of the device. Exchange information with your partner by asking and answering questions. Label all the components.
Student A Go to p.lll. Student В Go to p.113.
Together
decide how the device operates. Then compare
your explanation with the recording.
e
The power piston moves down the cylinder.
f When the displacer moves to the hot end of the cylinder, air is displaced to the cold end.
g This rotates the flywheel and moves the displacer piston back to the hot end.
2 Work in pairs. Decide which factor is the most important to the successful functioning of the engine. Can you explain why?
a The amount of heat applied
b The size of the flywheel
с The type of metal which the piston is made of
d The temperature difference between the ends of the
displacer cylinder
e The external air temperature
f The diameter of the displacer cylinder
3 What modern applications can you think of for the
Stirling engine?
Speaking
Study these statements about appropriate technology. Tick (\/) the ones you agree with and cross (X) those you disagree with.
1 Appropriate technology is only for poor countries.
T
echnology students should invent and make appropriate technology devices
Studying appropriate technology is a waste of time.
4
Appropriate technology is out-of-date technology.
2
Now compare your answers with your partner. Discussthe
statements you disagree about.
Useful language
Why do you think that...? In my opinion, appropriate
technology... Don't you think that...? My view is that...
32 Unit 5
plant (n) large indastrial
machinery
hire (v) let somebody use something for a short time, in return for payment
Pronunciation
Numbers and quantities
Read
out the numbers and quantities. Then listen and
check your answers.
a 3.142 e 16 KHz i 12V DC
b 1150 mm f 30 mA j 106
с 25ОМВ g 0°C k 1012
h 73%
1 40:1
d 60 GB
2
Listen
and write down the numbers and quantities in
figures.
a b
с d e f
g h i
j
» Go to Symbols and characters p.114
Vocabulary
Describing motion
1 Match adjectives 1-6 with the diagrams and adverbs A-F.
anticlockwise
clockwise
linear
oscillating
reciprocating
rotary
Movement
Adverb
Adjective
up and down, backwards and forwards
i
n
a straight line
from side to side
clockwise
anticlockwise
2Work in pairs. Take turns to cover each column of the table and test
your partner. Tell your partner to drawthe
arrows and say the vocabulary.
Appropriate technology 33
Explaining the difference between products
Work in pairs, A and B. Student A Go to p.lll. Student В
You are a customer at a plant hire company. You want to hire a portable generator for two weeks to provide power for your home. You don't want a noisy machine and you only want to fill the tank once a day. It must be easy to use and provide sufficient power for your home. You don't want to pay more than €40 a day.
Useful language
What's the output?
What kind of fuel does it use?
How often do I need to fill it up?
Is it easy to start?
How noisy is it?
How much will it cost?
Checklist
Assess your progress in this unit.
Tick (\/) the statements which are true.
I knowthe words to describe movement in a mechanism and the names for simple mechanisms
I can explain how a mechanism works
I can understand and say numbers and quantities accurately
I can explain the difference between products
My reading and listening are good enough to understand most of each text in this unit
Key words
Adjectives
rural
sound-proofed
two-stroke
Nouns
accelerator
compression
crankshaft
domestic appliance
exhaust gas
fuel
generate
pulley
Noun and verb
pump
Verbs
charge (batteries) engage (gears) wear
Note here anything about how English is used in technology that is new to you.
34 Unit 6
6 Crime-fighting and security
torch
provide
light, signal
witch
on
Look at the picture of the police officer.
Can you name any of the equipment he carries?
Listening
Crime-fighting equipment
Listen to a police officer talking about his equipment. As you listen, complete column A of the table with all the items he mentions.
Listen again and complete column В of the table with the function of the items.
Crime-fighting
and security 35
In this unit
key terms for crime-fighting and security equipment
how to describe the function of equipment
developing the skills of finding and exchanging information
writing a short report
.
Language spot
Describing function
• Study these examples:
Handcuffs are used to restrain someone. The knife-proof vest is used as body armour. Radios are used for contacting police headquarters. The baton is for keeping people at a safe distance.
• We can describe what things are used for, their function, in these ways:
used to + infinitive used as + noun (used) for + -ing
» Go to Grammar reference p.118
1 Match the items in the first column with their function in the second column.
1
tasers
a
help people know
exactly where t hey are
Personal Identification b incapacitate suspects Numbers (PINs) without serious injury
tagging с help protect air
travellers
4 anti-virus software d keep people at a safe
distance
face-recognition device e protect computers
helmet f admit only the right
people
7 batons g protect cards from
criminal use
Global Positioning h monitor convicted System (GPS) criminals
torches i head protection
10 luggage X-ray j signalling devices
equipment
2 Work in pairs. Take turns to ask and answer questions about the items in 1.
EXAMPLE
A What's the function of tagging? В It's used to monitor criminals. What are tasers for? A They're used to incapacitate suspects without serious injury.