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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

New challenges for animal science discussed

2006-04-04

Some of the guests attending the congress were from the left Dr Heinz Meissner (honorary president of the South African Society for Animal Science (SASAS) and senior manager at the Animal Production Institute of the Agricultural Research Council), Mr Paul Bevan (President of SASAS) and Prof Magda Fourie (Vice-Rector: Academic Planning at the UFS).
Photo: Lacea Loader

New challenges for animal science discussed

The South African Society for Animal Science (SASAS) is presenting its 41st Congress at the University of the Free State’s (UFS) Main Campus in Bloemfontein.

The congress started yesterday and will run until Thursday 6 April 2006. The theme is New challenges for the animal science industries.

It is one of the largest congresses in the 45 years since SASAS was founded in 1961. Among the delegates 12 African countries are represented, with the biggest delegation from Kenya. Delegates are also from the United States of America, Iran, Turkey, Germany, the Netherlands and Portugal and African countries like Zimbabwe, Mozambique and Botswana.

“Many of our members play an important role in the training of animal scientists at universities. The congress is specifically industry orientated so that scientists can interact with farmers through the respective producer organisations,” said Prof HO de Waal, Chairperson of the organising committee and lecturer at the UFS Department of Animal, Wildlife and Grassland Sciences.

According to Dr Heinz Meissner, honorary president of SASAS and a senior manager at the Animal Production Institute of the Agricultural Research Council, the National Livestock Strategy (NLS) Plan clarifies the role and responsibility of the livestock sector.

“Through this strategy we need to focus on enhancing equitable access and participation in livestock agriculture, improve global competitiveness and profitability of the livestock sector and ensure that the ventures implemented do not over utilise our resources,” said Dr Meissner.

In her welcoming address, Prof Magda Fourie, Vice-Rector: Academic Planning at the UFS highlighted the related challenges that the UFS will be focusing on specifically over the next five years. “We have identified five strategic clusters that represent broad areas of excellence in research and post-graduate education. Two of these are food production, quality and safety for Africa and sustainable development,” she said.

“The food safety and security cluster will focus on the production of food in all its varieties within the African context, encompassing the entire value chain – from production to consumption and nutrition related issues. This would include a strong emphasis on sustainable production systems,” she said.

According to Prof Fourie the rural development cluster will engage in questions around the role of higher education in sustainable development. “One of the focus areas in this strategic cluster pertains to sustainable livelihoods. It refers to a way of approaching development that incorporates all aspects of human livelihoods and means by which people obtain them,” she said.

Prof Fourie said that the challenges we are facing such as food production can only be effectively addressed through collaborative efforts. “That is why it is important that collaboration takes place between different scientific disciplines, researchers, institutions and countries who are confronted with similar difficulties,” she said.

According to Prof de Waal the congress will give key role players a unique opportunity to present a profile of what they perceive an animal scientist should be and state their specific requirement regarding the animal sciences and its applications.

“In this way we can determine what the industry’s needs are and we can re-align our curriculum to suit these needs,” said Prof de Waal.

During the next two days, various areas of interest will be discussed. This includes ruminant and monogastric nutrition, animal physiology, beef, dairy, sheep and ostrich breeding and sustainable farming covering the range from commercial to the small-scale farming level.

Media release
Issued by: Lacea Loader
Media Representative
Tel: (051) 401-2584
Cell: 083 645 2454
E-mail: loaderl.stg@mail.uovs.ac.za
4 April 2006

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