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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

“Breakthroughs depend on people believing in their own ideas”
2015-07-23


TED is a renowned international non-profit organisation dedicated to disseminating “ideas worth spreading” in the form compelling talks lasting up to 18 minutes.

Lerothodi Molete’s vision is to witness the youth of Bloemfontein emerge at the forefront of technological, scientific, and entrepreneurial innovations in both South Africa and the global arena.

 

Molete and Bonginkosi Leeuw are the organisers of TEDxUFS. Their duty is centered on inspiring people to believe in, and express, their ideas. These University of the Free State students have taken it upon themselves to inspire the youth to “push the boundaries of society.”

 

The second TEDxUFS event to be hosted by the university presents a unique opportunity for students, staff members, and the general public to mingle with influential speakers from across various disciplines.

 

Details of the event:

 

Date: Saturday 1 August 2015

Time: 08:00- 18:00

Venue: Albert Wessels Auditorium, Bloemfontein Campus

 

The keynote speakers include: Mmusi Maimane (Federal Leader: Democratic Alliance), Gareth Cliff (Radio personality: Cliff Central), Pieter Geldenhuys (Futurist), Brian Kally (Director: Arrow Logistics), Jonathan Jansen (Vice-Chancellor and Rector: UFS), Ricardo Peach (Director: Vrystaat Arts Festival, Pamela Nomvete (Former actor and writer), Gil Oved (Founder: Creative Counsel), Pepe Marais (CEO: Joe Public), Angelo Mockie (Senior Officer: Student Affairs and musician), Philippa Tumubweinee (Senior Lecturer in Architecture: UFS), and Melody Mentz (Psychology Senior Professor: UFS).

 

The reason behind the #AskWhy theme

 

"Why is a small word but it’s a quick, broad, sharp and abrupt one,” explains Leeuw. “It is the chosen word of the non-conformist, the defiant, and the visionary. It is a confrontational word. It challenges what is thought to be impossible.”

 

The ability to interrogate reality is what society and economies are built on. The absence of the fear to question encourages the capacity to progress.

 

Motivating young people to follow their dreams is the reason why the TEDxUFS team is persistent in their endeavours. Molete believes that, in order to change anything, people need to ask why.

 

Background of the innovation powerhouse called TED(x)

 

TED is a renowned international non-profit organisation dedicated to disseminating “ideas worth spreading” in the form compelling talks lasting up to 18 minutes.

 

In 1984, it was introduced as a conference exploring Technology, Entertainment, and Design. Three decades later, TED covers a wide variety of topics of global significance, reflecting the contemporary era in more than 100 languages.

 

TEDx events are under the TED umbrella. These events are organised independently, and create a platform for deliberating on local matters. The programme assists communities, organisations, and individuals to stimulate critical dialogue.

 

On 25 July 2014, the UFS hosted its inaugural TEDxUFS conference at the Odeion theatre on the Bloemfontein Campus, where eleven speakers addressed an audience of 150 people on interdisciplinary topics ranging from economics to entrepreneurship, technology, art, design, and theology.

 

This year, 200 seats will be available for innovative revolutionary individuals in search of inspiration.

 

Tickets are available at 0619284253 / 079 381 4126. Prices: R80 (Student/scholars) and R350 (Public/staff)

 

LINKS:

Lerothodi Molete- http://whoswho.co.za/lerothodi-molete-742022

Bonginkosi Leeuw- https://www.ted.com/tedx/events/10499

TEDxUFS- http://kovsielife.ufs.ac.za/templates/archive.aspx?news=276

Mmusi Maimane- http://whoswho.co.za/mmusi-maimane-44612

Garett Cliff- http://www.garethcliff.com/

Pieter Geldenhuys- http://pietergeldenhuys.com/

Brian Kally- https://za.linkedin.com/pub/brian-kally/4b/888/959

Jonathan Jansen- http://www.ufs.ac.za/adhoc-pages/rectorate/prof-(jd)-jonathan-jansen

Ricardo Peach- http://ricardopeach.com/

Pamela Nomvete- http://whoswho.co.za/pamela-nomvete-4789

Gil Ovid- https://za.linkedin.com/pub/gil-oved/3/910/892

Pepe Marais- http://joepublic.co.za/people

Angelo Mockie- https://za.linkedin.com/pub/angelo-mockie/27/56/302

PhilippaTumubweinee- http://natagri.ufs.ac.za/templates/staffmember.aspx?DCode=101&pid=zyNJm7KI%2b1k%3d

Melody Mentz- https://za.linkedin.com/in/melodymentz

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