Teachers notes
Professor Lawrence Lyons (1922-2010)
Physical chemist
Contents
Introduction
Summary of career
Extract from interview and focus questions
Activities
Keywords
You can order the DVD from us for $15 (including GST and postage).
Professor Lawrence 'Lawrie' Lyons was interviewed in 2008 for the Interviews with Australian scientists series. By viewing the interviews in this series, or reading the transcripts and extracts, your students can begin to appreciate Australia's contribution to the growth of scientific knowledge.
The following summary of Lyons' career sets the context for the extract chosen for these teachers' notes. The extract covers aspects of Lyons' research that he found especially rewarding and intriguing. Use the focus questions that accompany the extract to promote discussion among your students.
Lawrence Lyons was born in 1922, in Sydney. He began studying at the University of Sydney when he was 16 years old. In 1942 he completed an honours degree researching the effects of nitrogen and carbon monoxide on the photolysis of acetone. He received a PhD (1952) and a DSc (1964) from the University of London.
During the war years, he worked as a chemist at GE Crane and Sons in Sydney and was in the Air Force from 1943 to 1945. From 1945 to 1963 Lyons was at University of Sydney as a lecturer, senior lecturer and reader in chemistry. While at the University of Sydney, he investigated the physico-chemical properties of solids. Also during these years, he was instrumental in the establishment of the New University Colleges Council, which desired a stronger Christian presence on university campuses in Australia.
In 1963 Lyons became the first professor of physical chemistry at the University of Queensland. From 1970 to 1973 he was head of chemistry. He remained at the University of Queensland until his retirement and appointment as emeritus professor in 1987. He is a founder and member of the Institute for the Study of Christianity in an Age of Science and Technology.
Lyons' research has covered a number of areas of photochemistry (the study of the interaction of atoms and molecules with light or electromagnet radiation) including investigations into the fundamental electrochemical properties of organic molecules. The focus of much of his research has been the development of photoelectrochemical cells.
Over his career, Lyons has held a number of overseas fellowships and visiting professorships including at the University of British Columbia (1967), Tokyo University (1971), the University of Waterloo (1985) and Cambridge (1986). He received the Walter Burfitt Prize from the Royal Society of New South Wales in 1968 and the HG Smith Memorial Medal from the Royal Australian Chemical Institute, also in 1968. In 2001 he received the Australia Centenary Medal.
Lyons was elected a Fellow of the Australian Academy of Science in 1971.
Intriguing and rewarding aspects of science
What do you think was your most interesting scientific work – the things which gave you joy?
When I was in Harvard one year I published a paper on how you explain electronic properties of organic solids, the whole clutch of effects. For someone that worked in inorganic materials like silicon or the inorganic semiconductors, where you can use one-electron functions for quantum mechanics – the trouble with organic materials is that there you just can't do that. Any functions are mixed up. And it's beyond calculus.
Why did that particular work give you joy?
Well, it hadn't been done for any organic materials. It's just the whole range of effects: photoelectric thresholds of molecules and crystals, photoconduction thresholds, conductivity thresholds, molecular affinities, crystal electron affinities and so on. It wraps it all up. What you're doing is using certain experiments on molecules to get the answers to the quantum mechanics. But nobody has ever, I think, even to today, worked it out from absolute scratch. The functions are too complicated.
When I was a young don in Oxford and you came to visit me, you were working on photo cells, were you not?
Oh yes, there was work on photo cells. We went into cadmium telluride after the organics. And we showed that cadmium telluride was the most terribly sensitive substance on Earth in picking up impurities. None of the published analyses could be relied on. You bought material as 10-6 purity, and it wasn't. None of it was anything like that. You couldn't rely on purchased levels of impurity.
You couldn't touch the cadmium telluride with glass. It sucked whatever had got into the glass holes out of it into the cadmium telluride.
So that changed the electrical properties enormously?
Yes. Ultimately we bought SIMS [secondary ion mass spectrometry] and Auger analysis equipment and so on, and proved the point. Pure silica was a good material. It didn't have such hosts of impurities that glass – Pyrex – had. And Teflon was all right. You had to watch the surfaces to protect the cadmium telluride. Put in glass, it was hopeless. For a long while we didn't know what was going on, until we found we could increase the purity dramatically by avoiding glass surfaces all the way.
You mean even beakers and things of that kind?
Yes. If you bought the cadmium telluride as 5N standard or whatever, it wasn't.
An edited transcript of the full interview can be found at http://www.science.org.au/scientists/interviews/l/ll.
Focus questions
- Lyons researched photochemistry (the study of the interaction of atoms and molecules with light energy). Can you think of some photochemical reactions that occur at school or home?
- What did Lyons say was his most interesting scientific work? Why did he think this?
- Lyons discusses some of the problems he had when trying to use cadmium telluride as an alternative to silicon in photocells – specifically problems to do with impurities. Why might impurities be a problem for chemists?
Select activities that are most appropriate for your lesson plan or add your own. You can also encourage students to identify key issues in the preceding extract and devise their own questions or topics for discussion.
- Have students use library and internet resources to investigate photochemistry and photovoltaic solar cells. They report their findings as a poster or short presentation.
- Photovoltaic solar (Origin Energy, Australia)
Information and investigations where students learn about photovoltaic cells then estimate the contribution solar panels could make to their home electricity. - Effect of amount of light and wavelength on solar cells (National Solar Schools, Australia)
Students investigate how the spinning motion of a disc (attached to an electric motor powered by a commercially available solar cell) changes when the light hitting the solar cell causing it to spin changes. - Harnessing direct solar energy – a progress report (Australian Academy of Science )
This Nova: Science in the news topic explores how solar energy can be used. Includes a number of activities to do with photovoltaic cells. - Inside a solar cell (NOVA, USA)
Interactive which teaches about how photovoltaic solar cells work. Have students view the interactive and prepare a brief report about of what they’ve learned. - Florida Solar Energy Center (USA)
- Solar cell simulation
Outdoor activity which simulates how energy moves from the sun to a photovoltaic cell to the wire and to the load. Students move as electrons or photons in the simulation. - Solar powered system
Activities in which students learn that light energy from the sun can be turned into electricity with a photovoltaic cell and how different variables can affect the amount of power produced by a photovoltaic cell.
- Solar cell simulation
- Much of Lyons’ research has been basic research, not strictly applied research. Read Why do basic research? (National Institute of General Medical Sciences, National Institutes of Health, USA) and debate the merits of both kinds of scientific research.
atoms
molecules
organic chemistry
photo cells
photochemistry