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Dr Guy White was interviewed in 2010 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 Warren's career sets the context for the extract chosen for these teachers notes. The extract discusses how Warren first realised that there were bacteria living in the stomach. Use the focus questions that accompany the extract to promote discussion among your students.
Guy Kendall White was born in Sydney in 1925 but spent his early years in country New South Wales. In 1935 he moved to Rose Bay, Sydney where he attended Scots College. After high school, White completed a BSc (Hons 1) (1942-45) and an MSc (1946-47), both from the University of Sydney. During his university holidays, White worked at CSIR’s National Standards Laboratory on wartime projects. In 1947 he took up a CSIR Overseas Studentship to attend Oxford, graduating with a PhD in 1950. White’s PhD thesis entitled ‘Investigations on liquid helium’ involved research into the flow rates of liquid helium across different surfaces.
White returned to Australia as a research officer at the CSIRO Division of Physics (1950-53). Whilst here he measured the properties of materials at temperatures similar to those you would find in space. White moved continents again in 1953, this time to the National Research Council, Ottawa. Here he worked as a post doctoral fellow (1953-54) and then associate research officer (1955-58), measuring the transport properties of metal. The warm weather lured White back to the CSIRO Division of Physics where he worked as a principal research scientist (1958-62), senior principal research scientist (1962-69) and chief research scientist (1969-90). Over his long career at CSIRO, White investigated the conductivity, thermal expansion and magnetic interactions of materials, particularly at low temperatures.
While at CSIRO, White visited the prestigious Bell Laboratories in New Jersey as invited visiting scientist (1965-66) and the Universities of Oxford and Leeds as a senior visiting scientist (1976). The latter enabled him to update a new edition of his widely used text on Experimental Techniques in Low-Temperature Physics. Upon retirement, White was made an honorary fellow of the CSIRO Division of Materials Science and Engineering (formally the Division of Telecommunications and Industrial Physics) (1990 – 2008).
Dr White has been honoured throughout his career for his contributions to low temperature physics. Some of these honours include; fellowship of the Institute of Physics and foundation fellow of the Australian Institute of Physics (1961), Syme medal of the University of Melbourne (1966), Armco Iron award of the Thermal Conductivity Conference, USA (1983), Touloukian award from the American Society of Mechanical Engineers (1994), Honorary doctorate from the University of Wollongong (1994), member of the Order of Australia (2000) and Centenary medal (2001). Dr White was elected a Fellow of the Australian Academy of Science in 1970 and he served as councillor (1977-80) and vice-president (1979-80).
I got a real technical interest in measuring things, especially in terms of the aerospace age. People didn’t realise, that if you pick about five bits of copper off the shelf – one very high, one very pure and one ‘free machining’ copper, etc – at low temperatures the thermal conductivity can differ by a factor of a thousand. And these low temperatures are what you have up in space. This diagram here shows the thermal conductivity up this axis against temperature. The temperature is in what is called a ‘logarithmic scale’. It goes from one degree absolute, or -272oC, running up to 100 degrees absolute (-173oC) and up to higher temperatures. All these curves here represent the thermal conductivity of various types of copper. They show the enormous difference in their conductivities. At high temperatures they tend to come together but at low temperatures, where the conductivity is dominated by impurities, they are all vastly different. As I say, there is a factor of about a thousand between here and here (indicates). This is an ultra-pure copper – copper which probably has only impurities of one part in a million. Whereas down here we have other coppers, some of which contain up to half a per cent of tellurium. There is one here called ‘free machining’ copper.
Firstly, I looked at copper, silver, gold, magnesium and aluminium to get a feeling for those. I looked at their electrical resistance and tried to tie it in with what Klemens was doing in the theoretical area. Before the war, John Bardeen and Rudolph Peierls had done some work on this, as well as Dick Makinson at Cambridge. Incidentally, John Barbeen was the only man who ever won two Nobel Prizes in the one subject. Anyway, they had a simple theory using the scattering of waves that would determine the thermal conductivity and electrical conductivity in these metals. That is, scattering similar to sound waves or lattice waves. They worked out a theory of what it would be like at low and high temperatures. It turned out, when you went to measure them, that the theory was quite right. But the ratio of high temperatures and low temperatures was different by a factor of four or five. Klemens eventually explained this in terms of what are called ‘Umklapp processes’, as when the electron collides with a phonon. ‘Umklapp processes’ is German for ‘flip-over processes’.
It is a bit like Bragg reflection in X-rays. When you see an ocean wave coming against a wall, it reflects backwards. But if it hits a post, it just gets broken up into little bits. That’s really what Bragg reflection for X-rays is like, and these conductivities in metals are the same sorts of processes. This had been neglected in the early theories.
Focus questions
Select activities that are most appropriate for your lesson plan or add your own. These activities align with the Australian Curriculum strands ‘Science Understanding’, ‘Science as a Human Endeavour’ and ‘Science Inquiry Skills’, as well as the New South Wales syllabus Stage 6 Physics outcome 9.4.4. You can also encourage students to identify key issues in the preceding extract and devise their own questions or topics for discussion.
absolute
Celsius
conductivity
copper
Kelvin
metal
temperature
waves
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