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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

Student leaders 2012/13 announced

2012-08-30

Ready for the task - Sabelo Khumalo, SRC President of the Qwaqwa Campus and William Clayton, SRC President of the Bloemfontein Campus.
Photo: Johan Roux
31 August 2012

The 2012/13 elections for the Student Representative Councils (SRC) of the University of the Free State were completed successfully and show meaningful support for the changes in student governance adopted by students across campuses over the past two years.

The SRC elections at the Qwaqwa Campus were completed on 23 August 2012, while the elections at our Bloemfontein Campus took place on 27 and 28 August 2012.

The SRC Elections at our Bloemfontein Campus showed a voter turnout of 4516 votes (30.8%), with the elections at the Qwaqwa Campuses showing 1753 votes (46%) – both campuses reached the required quorums and the IEA (Bloemfontein Campus) and IEC (Qwaqwa Campus) declared the elections free and fair and announced the results as a true reflection of the will of the student bodies at the campuses.

The full SRC at Bloemfontein Campus now consists of 62% black and 38% white, and 53% female and 47% male members.

In the Qwaqwa elections, SADESMO achieved 46, 38% of the vote, with SASCO, PASMA and NASMO each achieving 30,23% and 8,39% and 14,26%, respectively.

The successful elections at Bloemfontein Campus show that the detailed transformation of student governance introduced by students at the Campus in 2010 and adopted by the university in 2011, succeeded in mobilizing greater participation of students in governance and representation. These changes in the main included a shift to independent candidacy for elective portfolios (12 seats) and organizational candidacy in nine sub-councils that holds ex officio seats on the SRC. Changes also included the establishment of student representative seats in faculty governance and management forums and the adoption of a reviewed Central SRC Constitution. Ex officio seats hold full and equal constitutional authority in the SRC.

Students at Qwaqwa Campus introduced additional portfolios to its SRC, including ex-officio seats for academic affairs, arts and culture, commuter students, Rag Community Service, religious affairs, residences and sports.

A joint sitting of the Campus SRCs will establish the Central SRC 2012/13 on 9 September 2012.

As a further opportunity for participation in and the development of student governance and representation, the current Central SRC herewith also announces its recent adoption of a student governance advisory programme, namely the UFS Student Elders Council (SEC).

The SEC is established as a combined programme between the Central SRC and the Dean of Student Affairs and will consist of selected senior student leaders from all campuses who completed their terms of office, apply and are appointed to the Elders Council by the Central SRC.

The Council will serve as an advisory structure to the Central SRC and other student structures in support of the continuous development of student governance and representation of the student body at the university.

The SEC will advise the Central SRC to be constituted following the constitution of the respective Campus SRCs.

The SRC members at the Bloemfontein Campus are:

President: Mr William Clayton

Vice-President: Mr Bonolo Thebe

Secretary: Ms Karis-Robin Topkin

Treasurer: Mr Pieter Coetzee

Arts & Culture: Ms Chanmari Erasmus

Accessibility & Student Support: Ms Gene McCaskill

First-generation Students: Ms Tanya Calitz

Legal and Constitutional Affairs: Ms Nokuthula Sithole

Media, Marketing & Liaison: Ms Neo Chere

Sport: Mr Tshepo Moloi

Student Development & Environmental Affairs: Ms Thabisile Mgadi

Transformation: Ms Koketso Mofokeng

Dialogue & Ex officio: Associations Council: Mr Anesu Ruswa

Academic Affairs & Ex officio: Academic Affairs Council: Ms Nombuso Ndlovu

Residence Affairs & Ex officio: Residences Council: Mr Johann Steyn

City Residence Affairs & Ex officio: Commuter Council: Mr Michael van Niekerk

Postgraduate Affairs & Ex officio: Postgraduate Council: Mr Fadeyi Akinsuyi

International Affairs & Ex officio: International Council: Ms Tumelo Moreri

Student Media Affairs & Ex officio: Media Council: Mr Jamal-Dean Grootboom

RAG Community Service & Ex officio: RAG Fundraising Council: Mr Jaco Faul

RAG Community Service & Ex officio: RAG Community Service Council: Ms Keneue Mahloana

The SRC members at the Qwaqwa Campus are:

President General: Mr S Khumalo

Deputy President: Mr P T Lenka

Secretary General: Mr D Khethang

Treasurer General: Mr S I Sithole

Media & Publicity: Mr S N Ntombela

Politics & Transformation: Tbc

Student Development & Evironmental Affairs: Tbc Academic Affairs: Mr T Molawude

Arts & Cultural Affairs: Mr T Nkohli

Off-Campus Students: Mr B Mtshali

RAG, Community Service & Dialogue: Ms S F Mlotya

Religious Affairs: Ms D C Khau

Residence & Catering Affairs: Ms Z Mzolo

Sports Council: Mr S Mngomezulu

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