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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

Enhancement of social justice focus at research colloquium
2010-10-07

At the third Education for Social Justice Research Colloquium the publication Praxis towards sustainable empowering learning environments in South were handed to Prof. Ezekiel Moraka, Vice-Rector: External Relations at the UFS. At this occasion were, from the left: Prof. Dennis Francis, Dean of the UFS Faculty of Education; Prof. Sechaba Mahlomaholo, Research Professor in the Faculty of Education Sciences at the North-West University; Prof. Moraka; and Dr Milton Nkoane, Senior Lecturer in the UFS Faculty of Education.
Photo: Leonie Bolleurs

 

This year, the University of the Free State (UFS) was the host for the Research Colloquium: Education for Social Justice for the very first time. It is the third time that this colloquium has been presented.

Prof. Ezekiel Moraka, Vice-Rector: External Relations at the UFS, opened the colloquium, stating that academics, through their research, are ultimately in a good standing to advise government on important issues such as social justice for them to address these issues accordingly.

Prof. Sechaba Mahlomaholo, Research Professor in the Faculty of Education Sciences at the North-West University, delivered the opening address on the theme: Validating community cultural wealth towards sustainable empowering learning environments for social justice. He said that the legacy of our recent past as South Africa still continues to haunt us, especially as exemplified in the dysfunctionalities that are rife in our education.

“With the colloquium we manage to bring together the ideas, thoughts, resources and efforts of educators and/or educationists concerned with the creation of a more equitable, equal, free, hopeful, peaceful and socially just society. Through our teaching, our community engagement and research activities we strive towards a more humane, caring, respecting and respectful South Africa and the world,” he said.

According to Prof. Mahlomaholo, education and its research are some of the most potent mechanisms at the very centre of social transformation. The papers at the colloquium focused on investigating, understanding and responding to issues of amongst others:

  • The medium of teaching and learning which continues to be a barrier to many learners to perform to the best of their abilities in the majority of the education institutions in South Africa;
  • Health, sexuality, HIV/Aids, stigmatisation and other deseases plaguing our communities currently;
  • Self-fulfilling prophecies and stereotypes about some learners not being as intelligent as the rest and this finally being reflected and confirmed in their poor academic achievements;
  • Differentiated levels of parental involvement in the activities of their children’s learning due to long absences from their families as they have to work in far-off places of employment;

Papers delivered at the colloquium moved beyond merely identifying the problems; they also suggested possible and plausible research-based solutions to these, such as integrating HIV/Aids education in curricula, listening to the aspirations of significant stakeholders such as mothers and parents generally in teaching and facilitating more rigorous community engagement practices.

At the colloquium gala dinner the book Praxis towards sustainable empowering learning environments in South Africa by authors Dr Milton Nkoane, Senior Lecturer in the UFS Faculty of Education, Prof. Mahlomaholo and Prof. Dennis Francis, Dean of the Faculty of Education at the UFS, was launched. The publication consists of a collection of the best peer-reviewed papers from a conference with the theme Creating sustainable empowering learning environments through scholarship of engagement. The main criterion for inclusion was that the paper should contribute to the theme by means of an original, tight, theoretical and empirical study conducted with the aim of informing the practice of creating sustainable empowering learning environments. The concrete cases examined in many of the chapters are very useful to helping readers understand the specific, on-the-ground concerns related to higher education and schools.

Media Release
Issued by: Leonie Bolleurs
Strategic Communication
Tel: 051 401 2707
Sel: 0836455853
Email: bolleursl@ufs.ac.za  
30 September 2010
 

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