ETF Light and Dark - Engineering the · PDF file• conduct an experiment to produce data...

1Engineering the Future

Light and DarkS2/S3

Scottish Charity Number SC004401 Scottish Charity Number SC015263

PROFESSIONAL ADAPTABLEINDISPENSABLEINVENTIVE CREATIVE

www.engineeringthefuture.info

Light and DarkEngineering Activity Teacher Guide


ContentsIntroduction

Outline of engineering activity

Engineering and learning principles

Learning outcomes

Curricular links

Structure and timing

Key resources

Activity 1: Introduction

Activity 2: Pupil experiment 1

Activity 3: Construction of circuit boards

Activity 4: Problem solving activity

Activity 5: Presentation

Also included:

Introductory Presentation

Pupil Instruction Sheet

Pupil Help Sheet

p 3

p 5

p 5

p 6

p 6

p 7

p 7

p 8

p 9

p 12

p 14

p 15

Unless otherwise stated, all content in this document is copyright (Copyright © 2009 University of Strathclyde and Copyright © 2009 University of Glasgow).

All rights are expressly reserved with the exception that a non-exclusive perpetual licence is granted to access, print, copy and use, without adaptation, the content available in this document for educational non-commercial activities only. Any content accessed, printed and copied must be accompanied by an acknowledgment of copyright.

It is forbidden to alter or adapt the content of the materials without the express permission of The University of Strathclyde and The University of Glasgow. This is to prevent inaccurate, misleading or inappropriate legal information being associated with either University.

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For further information or for queries please contact Research and Innovation at The University of Strathclyde, 50 George St, Glasgow, G1 1QE (www.strath.ac.uk/ri) or email [email protected].



IntroductionThe materials in this pack form one of a series of units which promote the teaching and learning of engineering in the secondary school curriculum.

The project development was developed by a partnership involving Woodfarm High School, East Renfrewshire Council, (Gurmeet Ghatoray), and the University of Glasgow Department of Electrical and Electronic Engineering, (Tim Drysdale).

This school-university partnership was one of a number of collaborative networks of school and university staff in Electrical and Electronic Engineering (EEE) created by the Engineering the Future project. These enabled staff and students from schools and universities to work together to create exciting and innovative programmes for school pupils, supported by world leading engineering research groups. These materials have already been trialled successfully in secondary schools across Scotland.

In the words of pupils involved: ‘It’s more fun, so you want to know more about physics.’ – ‘A lot of work: challenging but you’ve accomplished something, it ‘clicks’ and you remember it.’ – ‘… instead of being told step by step what to do you get to vary it yourself.’ – ‘…it just made you feel really smart once you’d done it.’

Engineering the Future is a 3-year project funded by a major grant from the UK Engineering and Physical Sciences Research Council (EPSRC) which is running from October 2006 to early 2010. It involves staff from the Department of Electronic and Electrical Engineering in the University of Strathclyde and from the Departments of Electronics and Electrical Engineering and of Educational Studies in the University of Glasgow and science teachers in some 20 secondary schools in 9 education authorities in Scotland and in 2 independent schools. The financial support afforded to the project by EPSRC is gratefully acknowledged as are the advice and encouragement provided by EPSRC and by the Universities of Strathclyde and of Glasgow.

Engineering the Future was planned in response to the general recognition that engineering in this country, in particular electrical/electronic engineering, faces serious challenges. The number of young people taking up university engineering



Science

MathsTechnology

Creativity & Innovation

Leisure

Health

Wealth Creation

Society

Industry

Infrastructure

Engineering

courses is low and becoming lower. Many young people – including ambitious high achievers – have very limited or distorted ideas about what engineering involves. In particular, they do not associate a creative, inventive, problem-solving and entrepreneurial approach to life and work with their science and mathematics work – an approach essential for equipping individuals with the skills necessary to meet the needs of today and the demands of tomorrow.

This is not a matter of academic interest. Engineers use science and mathematics, in conjunction with the tools of technology, to create new systems, infrastructures, devices, products and commodities for the overall benefit of society. There is an urgent economic need to embed and highlight engineering in the school curriculum. Engineering, the application of scientific and mathematical knowledge to practical issues, needs and problems, is fundamental to the creation of new technologies and sustainable industries. Engineering requires and supports the development of high levels of scientific and mathematical competence in the service of useful design, creativity, innovative thinking and problem-solving. It requires and fosters the confidence, drive, determination to succeed, teamwork and business acumen necessary to promote economic enterprise. There is an economic need for a larger number of engineers, high level engineering graduates and very capable technician engineers, with such skills to build a strong indigenous high-tech economic base.

We hope that you find these materials useful.



Teacher GuideOutline of engineering activityEngineering is the practical application of science and mathematics to find solutions to problems and to make functional products, such as automatic street lights. In this activity pupils take on an engineering problem and use their science knowledge to construct a simple electronic solution to a practical problem:

Modern street light turn on automatically at night – how does this work?

After an initial discussion as to the importance of why street lights should only turn on at night, students are presented with a light sensor (LDR) and asked to investigate how it reacts to light brightness. They then work through a staged process which illustrates how automatic street lights work.

Engineering and learning principlesThe context of this activity is key to promoting engineering and its importance in solving everyday problems. In this activity pupils should link their work to engineering in the following ways:

using scientific and mathematical knowledge and • understanding to solve everyday practical problems

understanding that an engineering solution to a problem • involves the construction of a system which is based upon scientific knowledge and understanding

collaborating in such a way that each person contributes in a • positive way to the final solution

using ICT in a manner which enhances their work•

recognising the importance of checking results.•



Learning outcomesPupils should be able to:

conduct an experiment to produce data on how the light • intensity (brightness) over an LDR varies with its resistance.

draw a distance/resistance graph for their LDR.•

use their data to help explain how an electronic system for • automatically switching on a bulb works.

explain how their LDR was used in solving the problem.•

understand that engineering is the application of scientific • and mathematical principles and knowledge to solve real problems.

Curricular linksThis activity will contribute the following Curriculum for Excellence statements of experiences and outcomes

ScienceSCN 4-09b By contributing to investigations into the properties of a range of electronic components, I can select and use them as input and output devices in practical electronic circuits.

SCN 4-09c Using my knowledge of electronic components and switching devices, I can help to engineer an electronic system to provide a practical solution to a real-life situation.

NumeracyMNU 3-01a I can round a number using an appropriate degree of accuracy, having taken into account the context of the problem.

MNU 4-20a I can evaluate and interpret raw and graphical data using a variety of methods, comment on relationships I observe within the data and communicate my findings to others.

LiteracyLIT 3-02a When I engage with others, I can make a relevant contribution, encourage others to contribute and acknowledge that they have the right to hold a different opinion. I can respond in ways appropriate to my role and use contributions to reflect on, clarify or adapt thinking.



LIT 4-21a I can use a range of strategies and resources independently and ensure that my spelling, including specialist vocabulary, is accurate.

The activity can also lend itself to a ‘rich’ or cross-curricular task with the Technology department.

Structure and timingTeacher introduction approx 15 min•

Pupil experiment 1 – LDR calibration approx 20 min•

Use of ICT for graph drawing, • printing and analysis of data approx 20 min

Pupil experiment 2 – Construction • of circuit boards approx 30 min

Problem solving activity approx 60 min•

Presentation and discussion of findings approx 30 min•

Key resourcesstandard metre stick•

standard 12 V Car bulb and holder•

12 V lab pack•

Philip Harris Unilab Alpha Electronics kit components •

o 1 x battery connector kit F4H76749

o 6 x yellow connector F4H27519

o 1 x light sensing unit F4H27982

o 1 x transducer driver F4H29437

o 1 x bulb unit F4H28275

digital multimeter Tait Components DT820B •

an appropriate graphing software dependant on availability • for establishment (e.g. ALBA software from djb microtech Ltd)



Activity1IntroductionThe introduction to the task can be based on energy saving street lights which can switch on automatically when it gets dark and switch off when it becomes light. The students may have already met the LDR as an input device.

Time requiredapprox 15 minutes

ResourcesIntroductory Light and Dark PowerPoint presentation



Activity 2Pupil experiment 1

This can be started as a quick class discussion paying 1. particular attention to fairness and how to change the light level over the LDR.

The pupils then set up the apparatus shown in figures 1 and 2. 2 to collect results for distance from bulb and LDR resistance.

12 V lamp on holder

metre stick12 V lab pack

LDR on light

sensing unit held in

clamp standohmmeter

across LDR

figure 1 figure 2



The pupils then use appropriate ICT software to construct 3. their graph. Sample results are shown below

A discussion should now take place which establishes that we have a sensor which can change its resistance when light levels change but how do we use this to do something productive? – USE A POWER SUPPLY!

distance (m)

resi

stan

ce (

Ω)

distance v resistance

1600

1400

1200

1000

800

600

400

200

0.05 0.10 0.15 0.20 0.25 0.30 0.35

0.1 0.12 0.14 0.16 0.18 0.2

0.22 0.24 0.26 0.28 0.3

0.32 0.34

954 1053 1140 1214 1278 1350 1398 1448 1484 1517 1550 1572 1580

Distance m c1

resistance ohms

c2




Resources

Standard metre stick•

Standard 12 V Car bulb and holder•

V lab pack•

Digital multimeter (Tait Components DT820B)•

An appropriate graphing software dependant on availability • for establishment (e.g. ALBA software from djb microtech ltd)



Activity 3

Pupil experiment 2 – Construction of circuit boards

In this stage the students begin by constructing a small 1.

figure 3 figure 4

potential divider circuit using the Unilab Alpha boards shown in figures 3 and 4. Note that if you use the light sensing unit from Unilab it is placed upside down.

Pupils should be asked to think about other ways in which 2. brightness sensed by an LDR can be varied.

The pupils are asked to note what happens to the voltage 3. reading when they cover the LDR with their hand and uncover it to change the brightness over the LDR.

Pupils are asked to consider in their work teams how this 4. knowledge can be used to address the problem of how to switch street lights on and off most efficiently.

After reporting back they are offered support (as required) to 5. construct the circuit shown in figures 5 and 6.



figure 5 figure 6

The students should be encouraged to vary the resistance 6. of the variable resistor to produce the desired effect with the lab lights ON and with the lab lights OFF and note the voltage across the LDR at which switching takes place.

Final discussions with pupils should centre around the 7. fact that the LDR used in the circuit is part of an electronic system in which –

LDR – input device•

Transducer driver – process device•

bulb/lamp – output device•


Resources

standard 12 V Car bulb and holder•

12 V lab pack•

Philip Harris Unilab (Alpha electronics kit components!) •

o 1 x battery connector kit F4H76749

o 6 x yellow connector F4H27519

o 1 x light sensing unit F4H27982

o 1 x transducer driver F4H29437

o 1 x bulb unit F4H28275

digital multimeter Tait Components DT820B•



Activity 4Problem solving activity: Keeping in the darkBackgroundIn order to grow mushrooms successfully on a commercial scale farmers have to be able to control accurately the temperature, light and ventilation in the growing sheds. If the growing conditions vary too much the mushroom crop will be reduced. For example, if farm workers leave the shed doors open daylight can spoil the crops and reduce the yield.

The problemThis engineering problem requires pupils to design and build an alarm system which will detect high levels of light and then to modify this design so that the system remembers that an alarm condition has been triggered.

Pupils should initially design and build an electronic system which will sound an alarm when the sensor detects bright sunlight. The alarm should sound continuously and stay on when the light intensity is high. When the light intensity falls the alarm should turn off. The system should include a way of adjusting the level at which the alarm is triggered.

Next the design should be modified by adding a warning light to the system. This light is to stay on if the alarm has been triggered until it is manually reset. This is to indicate to the farmer that the doors had been left open.



Activity 5

PresentationEach group must present their solutions to the class. The presentation can be in any format the group agrees but the following criteria must be followed:

Each member of the group will play a part in preparing the • presentation

The presentation must cover the following areas:•

o scientific knowledge about the ways that LDRs work

o the reasons why it is important to have an automatic switching system for street lights

o how LDRs can be used to switch lights on and off

o other possible uses for this technology

o an account of how the team worked

The presentation must include the following words (or • similar) in context

engineering

LDR

input device

process device

output device

calibration

resistance

ohms

light irradiance (or brightness)



The presentation should include appropriate diagrams. •

Each group presents their solutions to the class.•

Each group can be questioned after their presentation.•

Each group can be given feedback by another group.•


ETF Light and Dark - Engineering the · PDF file• conduct an experiment to produce data...

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