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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

Address by the first Inaugural President of the Central SRC

2005-08-03

The UFS Central SRC

Address by the first Inaugural President of the Central SRC of the University of the Free State, Mr Tello Motloung on Wednesday 3 August 2003

The Chairperson of the UFS Council, Judge Faan Hancke,
The Vice-chancellor and Rector of the UFS, Prof Frederick Fourie
The Vice-Rector Student Affairs of the UFS, Dr Ezekiel Moraka
The Presidents of the main campus SRC and the Vista campus SRC
Colleagues in the Central SRC, campus SRCs, students and fellow South Africans

Please receive my heartfelt revolutionary greetings

Vice-chancellor and rector what I bring here with me assisted by facts, is just the work of my imagination. Like a love letter addressed to a sweetheart miles away, even though you do not know how she feels, what she wants to hear, and do not even know what she looks like.

I value speech as just an honest intimation, that’s why I got into a habit of establishing a dialogue with people, looking at each other’s face, and persuading one another of what we are saying.

Vice-chancellor, today marks an important milestone in the history of the existence of the UFS. Today reflects the confidence and trust that students of the UFS have placed in us. They are confident that the Central SRC has both the will and the capacity to take our university forward as we confront the challenge of transformation.

Students are confident that they are correct to trust the Central SRC as the principal agent of change in our university that is genuinely committed to the objective of building a non-racial, non-sexist and democratic university. We need to frankly ask ourselves, as CSRC members, whether are we up to all these challenges?

All Central SRC members have to understand this fully, internalize it, and ensure that everything we do, does not betray the confidence and trust of students, or disappoint their expectations. I say this knowing that all Central SRC members have committed themselves to serve the students of the UFS, black and white, and no one among us (CSRC) needs any special lectures about this central commitment.

The UFS should be an omnibus, welcoming everybody on board. But we should be a bus with a clear direction. We will certainly lose our way if we, as an institution, don’t have a clear road map spelling out where we are heading to.

There should be clear guidelines on the role of students in the transformation process. Students should also be viewed as role players in transformation along with the University management, and not just opposing forces. There is no right time, other than this one, to move away from the politics of opposition to politics of transformation.

However, we need the support of management to do so. The University should value the role and contribution of student leaders, hear our legitimate claims and consider them as part of political and policy decision making.

Vice-chancellor and Rector, it remains our task to ensure that the UFS is transformed into an institution that is seen to be playing a vigilant role in developing students academically, intellectually, socially, culturally, politically and otherwise. The process of transformation is not ending tonight, it is just beginning tonight.

Judge Hancke, Prof Fourie, Dr Moraka, fellow students and fellow South Africans, I lead students at this university with a sense of pride and duty, and I know very well that I lead men and women, students who are all determined that we reach our destination safely and on time.

A navy divided within its ranks will be destroyed and vanquished by the enemy, but the navy united in purpose and action, loyalty and commitment will not sink but sail on to victory.

It is befitting to mention that every drop of my blood is telling me that the UFS is my home. I firstly became a student here, I became the SRC treasurer in my first year here, I became the deputy president here, and I became the first president of the Central SRC of the UFS.

Therefore you should never doubt my commitment towards the transformation of this university. To paraphrase what was said by students at another institution, “If there is no UFS in heaven, then I am not going.”

Let me conclude by thanking my ancestors for teaching me that even if I wined and dined with kings and queens, I am not a king myself, so I should not turn my back on people who made me what I am today.

Most importantly, I would like to thank the Almighty God and the grace of our Lord Jesus Christ for giving me time and power to lead this university.

It will be theoretically irresponsible if I ended my speech without indicating that “Only a Kovsie knows the feeling”.

I thank you.

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