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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

African Student Affairs Conference a huge success

2011-05-24

Mr Rudi Buys, UFS Dean of Student Affairs, Mr. Folabi Obembe, Managing Director of Worldview International, Ms Birgit Schreiber, Director of the Centre for Student support services at the University of the Western Cape, Dr. Augustinah Duyilemi, Dean of Student Affairs at the Adekunleh Ajasin University in Nigeria, Dr. Christina Lunceford, assistant Director for the Centre for Research on Educational Access and Leadership at California State University in America, and Prof. Cecil Bodibe, student affairs veteran and consultant.
Photo: Earl Coetzee

The African Student Affairs Conference (ASAC), which took place on our Main Campus last week, was a major success, with two days of lectures and discussions and two pleasant social gatherings, where delegates had the opportunity to get to know each other.

The conference, hosted on African soil for the first time, and co-hosted by the University of the Western Cape (UWC), started on Wednesday 18 May 2011 with an informal welcoming session. Delegates got to meet each other and Mr Rudi Buys, UFS Dean of Student Affairs, explained the meaning of South African words like "kuier" and "lekker'.

The official start of events took place on Thursday 19 May 2011, in the Reitz Hall in our Centenary Complex. The conference was attended by delegates from universities across the continent and aimed to place the focus on issues relating to student affairs in an African context.

Delegates shared and exchanged strategies, ideas and resources, and discussed issues related to the work of student affairs professionals. The conference hoped to promote an exchange of best practice and assist attendees in identifying successful programmes.

Among the topics discussed on the first day, were “Constructing Post-Conflict Democracy on campus: a case study of transformation of student governance and political engagement as post-conflict intervention”, by Mr. Buys, and a discussion on ways in which social and online media can be used to ease the challenges of student interaction, development and support, by Ms Birgit Schreiber, Director of the Centre for Student Support Services at UWC.

A panel discussion, led by Mr Buys and several members of our Interim Student Council (ISC), discussed the specific challenges faced at the UFS. The importance of buy-in from role-players in decisions taken by University management in order to ensure their success, was discussed, using the UFS and our recent changes as an example.

The successful integration of residences on campus inevitably came under the spotlight and the recently resolved Reitz-saga was named as a catalyst in getting students less apathetic and more involved in attempts at creating racial and social harmony.

Dr Christina Lunceford, Assistant-Director of the Centre for Research on Educational Access and Leadership at California State University, presented a paper entitled A National Approach to Building Capacity in Student Affairs in South African Higher Education.

She commented on the fact that there is little or no philosophical framework or explicit theory that informs practice of student services in South Africa.

According to Dr Lunceford, student development should be a key concern for every department or unit within student services and emphasized the need for a centralized student development unit at each university.
She also touched on the need for institutions to implement support from international student affairs professional associations, professional development for student affairs practitioners, the utilization of technology to support professionals in the field, and working with international partners to explore future opportunities, as ways in which student affairs can be used to drive performance and change at universities.

The conference continued in the Scaena theatre on Friday 20 May 2011, with presentations by Dr Augustinah Duyileme, Dean of Student Affairs at Adekunle Ajasin University in Nigeria, and Prof. Bobby Mandew, Executive Director of Student Affairs at the University of Johannesburg (UJ).

Dr Duyileme presented a paper on the challenges faced by Nigerian universities with regard to student conflict and protests, which often turn violent, and how such violence can be curbed through proper planning and management.

Prof. Mandew presented a very well-received presentation on UJ’s successful off-campus housing initiative, which involves home-owners and business owners in the areas surrounding their campuses.

Their approach demonstrated how proper planning can prevent problems associated with over-population in private homes and conflict with neighbours of the university, usually related to an influx of students into residential neighbourhoods.

This problem is faced by many universities, as more and more students flock to universities on the continent and campus residents cannot accommodate them.

The conference came to a close on Friday, with most delegates agreeing that the exchange of knowledge which took place was extremely valuable.

Ms Deborah Lahlan, of Nigeria, said: “This is an important conference for Africa and it should become a regular event.”

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