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18 April 2022 | Story Leonie Bolleurs | Photo Stephen Collett
Prof Ted Kroon
Prof Ted Kroon from the Department of Physics recently delivered his inaugural lecture on the topic What’s the use of a rainbow on the UFS Bloemfontein Campus.

“A rainbow is a natural phenomenon, the result of the refraction and reflection of the sun’s rays in drops of rain. As far as mankind is concerned, it’s a perfectly useless object and won’t make anyone money. Yet the poet who said, My heart leaps up when I behold a rainbow in the sky, only put into word the feeling of wonder and excitement we all have when we see a rainbow.”

“Every day I see a rainbow in my work; I do not need to wait to see one in the sky,” says Prof Ted Kroon, Professor in the Department of Physics at the University of the Free State (UFS), who used this phenomenon to introduce the topic of his inaugural lecture: What’s the use of a rainbow. 

“Far from being only a colourful spectacle with no practical value, rainbows are useful – and lead to useful things,” he believes. 

According to Prof Kroon, one can find examples of real rainbows and rainbow analogies used not only in everyday life, but also in physics. “Besides it being familiar devices in literature, culture, and even marketing, studies of rainbows can yield practical engineering information and may even help us to find new habitable planets,” he says.

Inspired by the many uses of a rainbow

In his lecture, he discussed the basic features of natural rainbows and how they come about. He also explored how the rainbow gives meaning to colour, and how this relates to the temperature of objects. He looked at an array of instances where the rainbow is used; from depicting the life of a star to indicating that we are sick (a thermometer) or when we need to refill a gas cylinder.
Moreover, Prof Kroon pointed out that rainbows are used in computer chips, stress identification, and to transmit internet data through underwater cables of glass fibre. He also referred to how the rainbow was harnessed as an engineering tool to measure refractive index and characterise fine droplet sprays used in industry. 

He continues, “Remarkably, the science developed to understand the natural rainbow can be redirected and applied to the optical properties of metallic nanoparticles, allowing the development of nanotechnology. Knowing how the natural rainbow works and its limitations, better systems have been developed to produce rainbows. Such rainbows have been used to discover new elements and to determine the age of the universe.”

As a member of an international community of phosphor researchers who are privileged to work with rainbows every day, he has used them to study the light-emitting properties of materials doped with bismuth. With this project – an initiative with the African Laser Centre taking place between 2016 and 2021 – he collaborated with the University of Khartoum in Sudan and trained a number of its postgraduate students. “My role included the guidance of students and the measurement and interpretation of the light-emitting properties of the materials. Our research during this time, considering more than a dozen materials, was summarised in 34 scientific publications that contributed to a greater understanding of bismuth ions as light-emitting materials,” he explains. 

Developing new materials, efficient in emitting blue light

He has been developing luminescent materials since 2006, primarily for general lighting (fluorescent tubes and LEDs) and displays (television, computer, and cellphone screens), as well as niche applications in medical and forensic science. 

As part of his current research, he is examining the effect of plasmonic metal nanoparticles on phosphor light emission. He is also exploring materials that absorb infrared light but emit visible light. “For this, I would like to consider the long-term stability of such materials and develop new materials that are more efficient in emitting particularly blue light,” he says. 

Prof Kroon holds a C2 rating from the National Research Foundation and has published more than 150 articles and book chapters, obtaining a Scopus h-index of 26.

News Archive

‘Is the South African university curriculum ‘colonial'?’ asks Prof Jansen
2017-11-24

Description: Jansen readmore Tags: Prof Jonathan Jansen, colonial, university curriculum, western knowledge

From left; Prof Corli Witthuhn, Vice-Rector: Research; former Rector and Vice-
Chancellor of the UFS, Prof Jonathan Jansen; Prof Michael Levitt, and
Prof Francis Petersen at the celebration lecture at the UFS.
Photo: Johan Roux

One of the critical issues that emerged from the South African student protests during 2015 and 2016 was a demand for the decolonisation of university curriculums. 

A senior professor at the Stellenbosch University, Prof Jonathan Jansen, said the number of people, including academics, who joined the cause without adequately interrogating the language of this protest, was astonishing. “The role of social scientists is to investigate new ideas … when something is presented to the world as truth.” Prof Jansen was speaking during a celebration lecture at the University of the Free State in Bloemfontein on 15 November 2017. 

Large amount of knowledge not African

He said the accusation is correct to a limited degree. “The objection, in essence, is against the centring of Western, and especially European knowledge, in institutional curricula.” There is no doubt that most of what constitutes curriculum knowledge in South African universities, and in universities around the world, derive from the West. “The major theories and theorists, the methodologists and methods are disproportionally situated outside of the developing world,” Prof Jansen said. 

The dilemma is, how will South Africa and the continent change the locus of knowledge production, considering the deteriorating state of public universities? “In the absence of vibrant, original, and creative knowledge production systems in Africa and South Africa, where will this African-centred or African-led curriculum theory come from,” Jansen asked. He says the re-centring of a curriculum needs scholars with significant post-doctoral experiences that are rooted in the study of education and endowed with the critical independence of thought. “South Africa's universities are not places where scholars can think. South African universities’ current primary occupation is security and police dogs,” Prof Jansen said. 

Collaboration between African and Western scholars
“Despite the challenges, not everything was stuck in the past,” Prof Jansen said. South African scholars now lead major research programmes in the country intellectually. The common thread between these projects is that the content is African in the subjects of study, and the work reflects collaboration with academics in the rest of the world. These research projects attract postgraduate students from the West, and the research increasingly affects curriculum transformations across university departments. There is also an ongoing shift in the locus of authority for knowledge production within leading universities in South Africa. Prof Jansen feels a significant problem that is being ignored in the curriculum debate, is the concern about the knowledge of the future. How does South Africa prepare its young for the opportunities provided by the groundswell of technological innovation? “In other parts of the world, school children are learning coding, artificial intelligence, and automation on a large scale. They are introduced to neuroscience and applied mathematics,” he said.

Prof Jansen said, in contrast, in South Africa the debate focuses on the merits of mathematics literacy, and what to do with dead people’s statues.

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