Latest News Archive

Please select Category, Year, and then Month to display items
Previous Archive
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

Kovsie community pledge to advance equality and eradicate racism
2015-04-15

Photo: Johan Roux

Photo Gallery 
Speech by JC van der Merwe

On Monday 13 April 2015, the University of the Free State drew a line in history. Staff and students united in a singular vision: equality.

Since March 2015, the Institute for Reconciliation and Social Justice, together with the SRC, has launched the No-to-Racism/Yes-to-Equality Campaign across all three campuses with tremendous success. This campaign has now reached a high point at which the Kovsie community pledge their commitment to entrenching a culture of equality at the university. The first pledge ceremony took place on 13 April 2015 at the Bloemfontein Campus. Kovsies thronged to place their inked thumbprints on pledge posters in an inspirational show of solidarity.

“The key to transformation,” Prof Jonathan Jansen, Vice-Chancellor and Rector of the UFS, said, “is putting yourself in the shoes of the other person.” When you look past yourself and acknowledge others’ experiences, the world starts to look different. A pledge, Prof Jansen continued, is a solemn promise – not only to stop bad behaviour, but to go forward resolutely with good behaviour. “You do not change a campus, you do not change a country, without being courageous,” Prof Jansen said.

The message from Mosa Leteane, President of the Student Representative Council (SRC), echoed the same belief. “Today,” Leteane said, “the UFS takes a bold and courageous step toward equality.” This new generation, which includes young people from all races, has started a new revolution. A generation that says no to discrimination and yes to equality. “We cannot afford to be ignorant or indifferent,” Leteane urged.

The remaining two campuses will also have an opportunity to publically pledge their support on the following days:
Qwaqwa Campus: Wednesday 15 April 2015
South Campus: Friday 17 April 2015

To enable the university to go beyond dialogues and consultation towards active decision-making, a University Assembly will be held on Tuesday 28 April 2015. The assembly will serve as a space for critical engagement among all university stakeholders to focus on issues such as symbols, policies, practices, and curriculum. Staff and students are encouraged to submit matters for discussion to JC van der Merwe (vdmjc@ufs.ac.za) before 22 April 2015.

The No-to-Racism/Yes-to-Equality Campaign is aligned with the declaration made by the UFS Council in November 2014, in which it states that “the Council of the University of the Free State believes very strongly in the human dignity, equality, and freedom of all people.”

We use cookies to make interactions with our websites and services easy and meaningful. To better understand how they are used, read more about the UFS cookie policy. By continuing to use this site you are giving us your consent to do this.

Accept