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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 launches projects to assist communities and current students
2011-03-16

Prof. Jonathan Jansen, UFS Vice-Chancellor and Rector and Mr Rudi Buys, Dean: Student Affairs, with learners at the  Bloemfontein-Oos Intermediary School.
Photo: Stephen Collett

The University of the Free State (UFS) has launched four exciting projects set out to improve the circumstances of its current and prospective students. These include a project that will honour dedicated and influential educators.

These community service projects in the starting blocks are: the UFS Schools Partnership Project, Extreme Make-over Project, Great Teachers Project and the No Student Hungry Campaign.
 
The Schools Partnership Project aims to support 21 schools across the Free State in helping them to become top achievers in the next three to five years. The schools involved were selected last year, after which the groundwork for the project was finalised. Although it mainly focuses on improving scholars' results in mathematics, accounting, physical sciences and English, it is also custom-designed according to the specific needs of the school, as indicated by the respective governing bodies beforehand. As a bonus, scholars of the schools involved will be given an opportunity to be introduced to student life; something Dr Choice Makhetha, UFS Vice-Rector: External Relations (acting), claimed to be of great importance. “We will invite Grade 10 to 12 learners to winter and summer schools being presented at the university. We will connect learners with students (one student adopts one learner for the day) for them to experience campus life. Grade 12 learners will also receive an invitation to the May 2011 graduation ceremony,” Dr Makhetha said.
 
Adding to the university's involvement at schools on local level, the newly upgraded Bloemfontein-Oos Intermediary School with its 112 UFS-sponsored tables will officially be revealed by the end of April. Although this school's upgrade showcases the power of partnerships, it is of special importance to the university, as it also marks the first school to receive an extreme make-over as part of the 'Extreme Make-over for Schools Project'. This project, in conjunction with the local business community, university staff and students, the community, the Department of Basic Education and SIFE (Students in Free Enterprise), is considered to be a flagship project of the Vice-Chancellor and Rector, Prof. Jonathan Jansen. Part of the project’s agreement includes visits from a group of about 100 students representing campus initiatives such as the UFS’s Kovscom, Rag and SIFE, which will contribute to the improvement of the schools' resources within a period of 10 – 15 weekends. “We invite support from all corners. South Africa has a business community committed to improving the social circumstances of its community and we plead that they also come to the rescue of the Bloemfontein-Oos Intermediary School,” said Dr Makhetha.
 
By spreading a 'can do' attitude, the UFS aims to honour noble and remarkable teachers across the country by means of its 'Great teacher's project'. Through the project, fellow citizens are encouraged to submit their stories on their former or current teachers’ dedication and their positive impact which are often overlooked. The panel of seasoned education scholars and practitioners will select the top 500 stories based on the stories' clarity, distinctiveness, plausibility and affectability, which will be perpetuated in a book called 'Great Teachers', to be released at the end of this year. Proceeds are destined to serve as bursaries for students who wish to pursue a career in education. According to Prof. Jansen the ideal teacher is: “Somebody who was among, but stood out above, their colleagues, a person who made a lasting impact long after the details of subject matter content of examination preparation were forgotten.”
 
Regardless of this exceptional effort of supporting schools across the province, the UFS remains committed to its students and their social welfare by means of the 'No student hungry' campaign. This project provides financially challenged students the opportunity to purchase food from the Thakaneng Bridge on the Main Campus in Bloemfontein by using their student cards at two selected kiosks serving balanced meals. The project, which is under the guardianship of Ms Grace Jansen and Dr Carin Buys, relies solely on several fund-raising projects across the country. These women are the respective spouses of the Rector and Dean: Student Affairs, Mr Rudi Buys. According to Ms Jansen this initiative was proposed after UFS staff reported that many students were struggling to concentrate on their studies due to hunger pangs. Although the campaign recognizes students with strong academic records, it doesn't overlook those who need a food bursary which might result in them dropping out. Ms Jansen said as the external funds gathered increase, so will the amount of students being supported by the project. “The plan is to continue until the fate of hungry students had come to an end,” she said.
 

Media Release
14 March 2011
Issued by: Lacea Loader
Director: Strategic Communication
Tel: 051 401 2584
Cell: 083 645 2454
E-mail: news@ufs.ac.za

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