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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

Prof. Iain Benson delivers inaugural lecture in UFS's Faculty of Law
2010-10-27

Prof. Shaun de Freitas (left) of the Faculty of Law at the UFS and Prof. Iain Benson.

Prof. Iain T. Benson delivered his inaugural address as Professor Extraordinary in the Department of Constitutional Law and Philosophy of Law in the Faculty of Law at University of the Free State (UFS) faculty last week.

Originally hailing from Canada and currently residing with his family in France, Prof. Benson is an academic with a wealth of experience and expertise in the field of law, especially with regard to the right of conscience and religion. His achievements number many, including being a Senior Associate Counsel at one of Canada’s leading law firms, Miller Thompson LLP; and serving on the Founding Board of the Global Centre for Pluralism. 

Apart from his work on leading cases in the United Kingdom and Ireland, Prof. Benson also has strong ties with the law in South Africa. He is part of the Continuity Committee that is responsible for the major undertaking of drawing up the South African Charter of Religious Rights and Freedoms in cooperation with all the major religions in South Africa which, when completed, will be the first use of Section 234 of the South African Constitution.

The title of the inaugural lecture was Living together with Disagreements and the Limits of the Law, which tackled various conscientious and topical issues regarding the complex relationships between the law and religions. Starting off the lecture, Prof. Benson recalled that living together with disagreement is a necessary achievement in free and democratic societies and that differences of belief and opinion should not be resolved by force acceptance of a “one-size fits all” model. Mentioning religion and same-sex marriages, Prof. Benson held these up as issues which reasonable people may disagree on and should hence be respected by the public sphere that is girded round by the law. 

Quoting Sophocles’ Antigone, Prof. Benson noted that tensions between the so-called divine and imminent or state laws as in a non-theocratic state have always been with us. He stressed the importance of a wide respect by the law for civic associations in addition to but particularly in relation to religion which guides citizens views about wrong and right beyond matters that are regulated by law.
 

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