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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 changes format of graduation ceremony

2011-04-17

The highest number of qualifications in the history of the University of the Free State (UFS) will be awarded at the autumn diploma and graduation ceremony from 9-11 May 2011, which will be held in the Callie Human Centre on our Main Campus in Bloemfontein.

From this year, the format of the ceremony will change to make it more visible to students and the public. For the first time, all the doctoral and master’s degrees from each respective faculty will be conferred during one ceremony on 11 May 2011, instead of each faculty handling these qualifications individually. Another change in the format is that the procession will gather on the Red Square in front of the Main Building and move to the Callie Human Centre from there. Both academic staff and graduands will partake in the procession.

A total of 3 674 qualifications will be conferred during this year’s graduation ceremony, including 629 diplomas, 2 613 Bachelors and honours degrees, 372 master’s degrees and 58 doctorates.

An honorary doctorate in Drama and Theatre Arts will also be awarded to theatre stalwart Mr Pieter Fourie. He is one of the most acclaimed Afrikaans playwrights in South Africa and probably the only person to have left his mark as an actor, director, artistic director and writer.

Mr Fourie was awarded the Gerhard Beukes prize for drama , was honoured for his contribution to the arts by the South African Academy for Science and Arts and was appointed as trustee of the Arts and Culture Trust of the State President in 1997. He has also served as a committee member of the South African Academy for Science and Arts.

Mr. Fourie has also been the proud recipient of the Hertzog prize for drama, two FNB-Vita awards and a Fleur Du Cap award.

The full programme for the respective ceremonies is as follows:

Monday, 9 May 2011:

At 08:30, certificates and diplomas, excluding PGED and PGES, will be awarded to graduates from the Faculty of Education and at 12:00 PGED, PGED and B and honours degrees will be awarded to students from the same faculty. At 15:30 on the same day, certificates and B and honours degrees will be awarded to students in the Faculty of the Humanities.

At 19:00, the Faculties of Education, the Humanities and Economic and Management Sciences will have their prize-giving ceremonies for outstanding achievers.

Tuesday, 10 May 2011:

At 08:30, students in the Faculty of Economic and Management Sciences will graduate and at and 12:00 the Faculty of Natural and Agricultural Science will join them. This includes students in BML, B.Admin., B.Pub. and related honours degrees. At 15:30, 503 students from the Faculty of Natural and Agricultural Sciences will receive their certificates, diplomas and B and honours degrees.

At 19:00, the Faculties of Health Sciences, Natural and Agriculture Sciences, Law and Theology will have their prize-giving ceremonies.

Wednesday, 11 May 2011:

The Faculty of Health Sciences, the Faculty of Law and the Faculty of Theology will be awarding their certificates, diplomas and B and honours degrees at 08:30. At 12:00, all faculties will award a total of 372 master’s degrees and at 15:30 a total of 58 doctorates will be conferred.

The Chancellor’s Dinner will take place in the Centenary Complex on the Main Campus of the UFS at 19:00.

The graduation ceremony of our Qwaqwa Campus will take place in the Rolihlahla Mandela Hall on the Qwaqwa Campus on 7 May 2011 at 10:00. All the faculties at this campus will confer their degrees, certificates and diplomas at this ceremony.

Media Release
21 April 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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