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Dr William Blevin 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 Blevin's career sets the context for the extract chosen for these teachers notes. The extract explains the importance of standards and units of measurement and Blevin's work in the field of measurement of light. Use the focus questions that accompany the extract to promote discussion among your students.
William Roderick (Bill) Blevin was born in Inverell, NSW in 1929. He completed his secondary schooling at Tamworth High School (1945) before deciding, in a circular fashion, to study at New England University College (NEUC) to become a science teacher. Blevin graduated with a BSc (Hons 1) in physics in 1950. His honours year in research was spent investigating molten and discoloured “hot spots” left on metal electrodes by high current electric arcs of short duration. Blevin continued this research for his masters of science (MSc, 1952). He completed his DipEd in 1951 and spent a year as a lecturer in physics at NEUC.
In 1953 Blevin joined the CSIRO Division of Physics as a research scientist. Here he led the optical radiometry group and progressed to chief research scientist in 1976. During this time he was awarded a DSc from the University of New England (UNE, 1972). Blevin served as acting chief (1979-80), assistant chief and chief standards scientist (1980-88) and finally chief (1988-94) of CSIRO Division of Applied Physics before his retirement in 1994. One of Blevin's major achievements while at CSIRO was to have the SI unit of light intensity (the candela) redefined in 1979 to be on a firm physical basis.
During Blevin's career he was also active in the international standards community. He served as president (1980-96) of the Consultative Committee for Photometry and Radiometry, and as vice-president (1992-96) and secretary (1997-2000) of the Comité International des Poids et Mesures (CIPM, the International Committee of Weights and Measures). In 1998, at the request of CIPM, he completed a strategic plan for the 21st century for the worldwide measurement system and, in particular, for the Bureau International des Poids et Mesures (BIPM, the International Bureau of Weights and Measures), located at Sèvres in France.
Blevin's contributions to the fields of applied physics and metrology have been recognised through the awarding of multiple honours including; election to the fellowship of the Australian Academy of Technological Sciences (1983), membership of the Order of Australia (1989), UNE distinguished Alumni award (1995), and the Centenary Medal (2003). Blevin was elected a Fellow of the Australian Academy of Science in 1985 and served the Academy as a council member (1991-94) and vice-president (1992-93). In addition he was awarded the Matthew Flinders medal and lecture (1996) and was the Lloyd Rees memorial lecturer (1996).
What did the National Standards Laboratory (NSL) do, particularly in those days, and what was the bit of its work that you were involved in?
Well, CSIRO had been around for quite a while but, prior to the war, most of its work had been in biological sciences and it was interested in the application of science in industry and so on. The decision was made just prior to the war, not to do with the war but independently, that it should get more into physical sciences and one of the first things recommended was to set up a national standards laboratory that would maintain Australia's physical standards of measurement. The NSL would be the final arbiter as to how long a metre was, how long a second lasted and all sorts of units, including nuclear quantities etc.
They really set out thinking that the NSL would be a subset of the National Physical Laboratory (NPL) in London, which had had that job for Britain since about 1900. Most of the major countries had set up national laboratories at about that time. Certainly they had done so in Russia, in Germany and in the USA. So Australia came to the party some 40 years later. NSL quickly became the leading organisation in Australia's national measurement system, collaborating closely with the National Standards Commission (NSC) involved in legal metrology, the National Association of Testing Authorities (NATA) involved in laboratory accreditation, the Standards Association of Australia (SAA) involved in documentary standards, and the States' Offices of Weights and Measures which took care of trade measurements.
Soon after the war, NSL was structured as three Divisions of CSIRO. One was Metrology, dealing with length and mass and a lot of things like that; one was Electrotechnology; and another one was Physics, which had temperature, light and the other bits. The bit that I was brought in to do was probably one of the least accurate ones and that was basically what they called the photometry section, which is the measurement of light. Light had been measured for over 100 years and it was different from the other units in that the detector used to measure light was traditionally the human eye. There were few other useful detectors at that time. So photometry essentially had a biological element to it. Right up to World War II, most measurements in photometry were done visually with special instruments. It's amazing how accurately the eye can compare the brightness of two patches of light, provided that certain conditions are met. But photocells were starting to appear and there was starting to be a move towards physical methods of measuring light.
We were also interested in a subject called radiometry or optical radiometry, which is a similar subject: you're still measuring radiation, but you're not taking any account of the visual effect. So you measure optical power in watts, just like you measure electrical power in watts and so on. Colorimetry was more related to photometry; it took into account physiological effects. It was more complicated than photometry because, with photometry, particularly in daylight, there is one curve that more or less tells you how sensitive the eye is to the different colours of the spectrum. It's a bell shaped curve, peaking in the yellow-green and falling off rapidly at each end of the spectrum. In colorimetry you need three curves and you can actually measure colour digitally and end up with numbers and uncertainties and so on, just like other physical quantities.
But the range of interest in these subjects just amazed me, really. It was far from limited to just providing standards for Australian lamp manufacturers. For example, we collaborated extensively in the development of improved street-lighting technology and of more effective colour signals for road traffic, airport runways and maritime applications; and we encouraged and assisted a wide range of manufacturers to adopt physical rather than visual methods to control the colour of their products. There were scientists requiring assistance in developing deep-sea photometers to measure light deep under the water. There were other people who were researching aurorae in Antarctica and wanted accurate calibration of an artificial aurora that they had made as a reference standard. You had to sit in the darkroom with it for half an hour before you could even see it and then they still wanted to know how bright that was, in the photometric units. With the Vietnam War, I remember the great trouble that the military had in measuring some of their high-intensity flares that were shot high in the sky and lit up the countryside, and we were able to sort out what was wrong with their apparatus.
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.
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