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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

UFS presents first Beyers Naudé Memorial lecture
2010-09-16

At the Beyers Naudé   Memorial lecture were, from the left: Prof. Jonathan Jansen, Rector and Vice-Chancellor of the UFS; Rev. Cedric Mayson; and Mr Kgotso Schoeman, Chief Executive Officer of Kagiso Trust.
Photo: Dries Myburg

The seventh Beyers Naudé Memorial lecture was presented for the first time at the University of the Free State (UFS) this week. This lecture that is presented at a different university each year took place on the Main Campus of the UFS in Bloemfontein this year. Rev. Cedrick Mayson presented the lecture with under the theme: Crafting a legacy.

According to Rev. Mayson more deeply rooted forms of suppression came forward after the democratic elections in 1994. Liberation from apartheid was, according to Mason, very superficial. The poor were still severely suppressed at economic, political, cultural, religious and environmental level. “We have to apply Beyers Naudé’s legacy of liberation in these areas,” Rev. Mayson declared.

“The system according to which the rich become wealthier and the poor become poorer must be replaced by a system where everybody can have enough. This is only possible with the insight of the oppressed.

“The government and the opposition are dominated by people who seek advantage for their own gain. Regardless of democratic slogans and some enlightened individuals’ rules against corruption and violence, we lack the political will to engage in the transformation of the whole world for the good of all earthlings,” said Rev. Mayson.

According to him, consumer culture has become a fine-tuned instrument for keeping people incomplete, shallow and dehumanised.

“Religions are self-centred. Leaders from most of the religious groupings criticised apartheid but they never joined the struggle to assist in demolishing apartheid. It appears as if religious institutions are not able to address the causes of poverty because they themselves are too rich and too powerful,” said Rev. Mayson.

He ended with the following words: “What we need is a leap of faith. Beyers knew that. The world is waiting for people to claim their legacy and to accomplish a post-religious secular spirituality of ubuntu.”

Rev. Mayson is a former Head of Religious Affairs of the ANC. He had also been a former staff member of the Christian Institute before it was banned. Furthermore, he was the Editor of Pro Veritate. Before he retired, he had also been involved in the South African Council of Churches and the World Conference for Peace.

The memorial lecture, a collaborative effort of the UFS and Kagiso Trust, endeavours to involve South Africans in dialogue about issues that affect our nation. This year the lecture was presented at the UFS for the first time and it will take place on the Qwaqwa Campus of the UFS next year.

Media Release
Issued by: Mangaliso Radebe
Assistant Director: Media Liaison
Tel: 051 401 2828
Cell: 078 460 3320
E-mail: radebemt@ufs.ac.za  
16 September 2010
 

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