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TED Talks about rainbows

18 April 2022 | Story Leonie Bolleurs | Photo Stephen Collett

“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 sets trend for higher education institutions

2005-09-21

The University of the Free State (UFS) offers more service-learning courses than any other higher education institution in the country and has the highest number of students enrolled for these service-learning courses.

This was the research findings on higher education institutions conducted between 2001 and 2004 by the Joint Education Trust (JET) into service-learning courses. These are courses which seek to integrate service to the community into the academic core of higher education institutions.

The results of this research indicated that the UFS is one of the few higher education institutions in South Africa that have made progress in integrating community engagement into the mainstream academy.

According to the findings 2 233 students at the UFS participated in service-learning courses supported by JET, while 858 students at the University of Transkei (UNITRA), 636 students at the University of the Western Cape (UWC) and only 600 students at the University of the Witwatersrand (WITS) participated in service-learning courses.

In total there were 6 930 students participating in service learning courses supported by the JET at 10 institutions throughout the country.

The research also found that out of a total of 182 service-learning courses supported by JET countrywide, the UFS had the highest number of such courses at 42, followed by WITS with 28, the University of Kwazulu Natal with 26, UWC 24 and UNITRA with 22.

Nationally, most of the service-learning courses at higher education institutions are offered in the human sciences (62), followed by health sciences (37), education (26), agriculture (14), and economic sciences (11).

According to leading academics, service-learning is a credit-bearing, educational exercise in which students participate in an organised service activity that meets identified community needs and helps the student to gain a deeper understanding of course content and a sense of civic responsibility.

Reacting to the research findings, the Rector and Vice-chancellor of the UFS, Prof Frederick Fourie, said the university feels strongly that there should be integration of service-learning into the academic core of the institution.

“Through service-learning modules the UFS can give expression to its role of service to the community as an institution of higher learning, producing quality graduates who understand the communities in which they will have to function for the rest of their lives,” Prof Fourie said.

According to Mr Jo Lazarus, the project manager of the Community-Higher Education – Service Partnership (CHESP), which falls under the JET, a number of institutions have identified community engagement as a strategic priority and have allocated significant resources from their central budget towards its implementation.

Mr Lazarus said most students have an overwhelmingly positive attitude towards service learning.

“A large percentage of students surveyed indicated that their service-learning course helped to improve their relationship skills, leadership skills and project planning abilities. As significant is the fact that these courses also benefited them in terms of their awareness of cultural differences and opened their eyes about their own cultural stereotypes,” said Mr Lazarus.

“The key challenge still hampering the integration of service-learning as a core function of academic activity is that some institutions still see service-learning as an add-on, and nice-to-have activity,” he said.

According to Mr Lazarus higher education must demonstrate social responsibility and commitment to the common good by making available expertise and infrastructure for service-learning as a form of community engagement.

Media release
Issued by:  Lacea Loader
   Media Representative
   Tel: (051) 401-2584
   Cell: 083 645 2454
   E-mail: loaderl.stg@mail.uovs.ac.za
   20 September 2005

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