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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

Moshoeshoe film screened at UFS as part of transformation programme
2004-10-14

A ground-breaking documentary film on the life and legacy of King Moshoeshoe I, the founder of the Basotho nation, will be screened at the University of the Free State (UFS) tonight (Wednesday 13 October 2004) at 19:00.

Rector and Vice-Chancellor of the UFS, prof. Frederick Fourie, said the UFS commissioned the documentary as a practical demonstration of the university’s commitment to the continued transformation of the campus and the creation of a new inclusive institutional culture for all staff and students.

It is part of a larger UFS project to honour the Moshoeshoe legacy of nation-building and reconciliation and to explore his role as a model of African leadership.

The documentary tells the life story of the legendary king, with emphasis on his remarkable leadership skills, his extraordinary talent for diplomacy and conflict resolution and his visionary commitment to creating a new nation from a fragmented society.

Almost all the filming was done on or around Moshoeshoe’s mountain stronghold, Thaba Bosiu.

The last part of the documentary explores the lessons for African leadership to be learnt from Moshoeshoe. The hour-long documentary film was produced by the well-known journalist Mr Max du Preez and was commissioned by the UFS as part of its centenary celebrations.

“Through this documentary film about King Moshoeshoe, the UFS commits itself to developing a shared appreciation of the history of this country,” said prof. Fourie.

“King Moshoeshoe was a great African statesman and leader. He was born in this region of the country, but his influence and legacy extends way beyond the borders of the Free State, Lesotho and even way beyond the borders of South Africa,” said prof. Fourie.

As part of the larger project, the UFS is investigating a possible annual Moshoeshoe memorial lecture that will focus on African leadership, nation-building and reconciliation, possible PhD-level research into the life and legacy of King Moshoeshoe and a literary anthology including prose and poetry.

“We must gain a deeper understanding of what really happened during his reign as king. Therefore the University of the Free State will encourage and support further research into the history, politics and sociology of the Moshoeshoe period, including his leadership style,” said prof. Fourie.

According to prof. Fourie the Moshoeshoe project will enable the UFS to give real meaning to respect for the diversity of our languages and cultures, and the unity South Africans seek to build as a democratic nation through such diversity.

According to the producer of the documentary, journalist Mr Max du Preez, the UFS deserves credit for recognising this extraordinary man and for financing this important documentary.

Du Preez said: “It was about time that South Africa rediscovered Moshoeshoe. Colonialist and Afrikaner Nationalist historians have painted him as a sly, untrustworthy and weak leader. Most historians have preferred to glorify leaders in South Africa’s past who were aggressors and conquerors. In the process most present-day South Africans came to regard Moshoeshoe as a minor tribal figure.”

“Yet this was the man who broke the cycle of violence, famine and suffering during the traumatic time in central South Africa in the early 1800s. During the entire 19th century, Moshoeshoe was virtually the only leader in South Africa who did not answer violence with violence, who did not set forth to conquer other groups and expand his land,” said Mr du Preez.

“I have no doubt that the stability that the Free State region has enjoyed over more than a century was largely due to Moshoeshoe’s leadership and vision. He can quite rightly be called “The Nelson Mandela of the 19th Century,” Mr du Preez added.

Explaining the title of the documentary film, Mr du Preez said: “We decided to call the documentary “The Reniassance King” because whichever way one looks at it, Moshoeshoe symbolised everything behind the concept of an African Renaissance.”

“He was progressive, just and fair; he deeply respected human life and dignity (we would nowadays call it human rights); he embraced modernity and technology without ever undermining his own people’s culture or natural wisdom; he never allowed European or Western influence to overwhelm him, make him insecure or take away his pride as an African,” said Mr du Preez.

“Moshoeshoe was the best of Africa. If only contemporary African leaders would follow his example of what African leadership should be,” Mr du Preez said.

Among the interviewees in the film were Lesotho’s most prominent historian, Dr LBBJ Machobane, the head of the UFS’s Department of History, prof. Leo Barnard, Moshoeshoe expert and Gauteng educationist Dr Peter Seboni, Lesotho author and historian Martin Lelimo and Chief Seeiso Bereng Seeiso, Principal Chief of Matsieng and direct descendant of the first King of the Basotho.

The documentary film on King Moshoeshoe will be screened on SABC 2 on Thursday 4 November 2004.
 

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