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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

Project aims to boost science pass rate
2009-01-19

 
Attending the launch of the HP grant of about R1 million to the UFS are, from the left: Mr Leon Erasmus, Country Manager for HP Technology Services in South Africa, Prof. Teuns Verschoor, Acting Rector of the UFS, and Mr Cobus van Breda, researcher at the UFS's Centre for Education Development and manager of the project.
Photo: Lacea Loader
The University of the Free State (UFS), in partnership with computer giant Hewlett Packard (HP), wants to boost the pass rate of its science students by using mobile technology.

The UFS is one of only 15 universities across Europe, the Middle East and Africa and the only university in South Africa to receive a grant from HP to promote mobile technology for teaching in higher education valued at USD$ 100,000 (or about R1 million). Altogether 80 universities from 28 countries applied for the grant.

“Last year HP invited a number of selected universities to submit proposals in which they had to explain how they are going to utilise mobile technologies in the redesign of a course that is presented at the university. The proposal of the Centre for Education Development (CED) at the UFS entitled “Understanding Physics through data logging” was accepted,” says Mr Cobus van Breda, researcher at CED and manager of the project.

According to Mr van Breda, students who do not meet the entrance requirements for the three-year B.Sc. programme have to enroll for the four-year curriculum with the first year actually preparing them for the three-year curriculum.

In order to increase the success rate of these students, the project envisages to enhance their understanding of science principles by utilising the advantages of personal computer (PC) tablet technology and other information and communication technologies (ICT) to support effective teaching and learning methodology.

“By using PC tablet technology in collaboration with data-logging software, a personal response system, the internet and other interactive ICT applications, an environment different from a traditional teaching milieu is created. This will consequently result in a different approach to addressing students’ learning issues,” says Mr van Breda.

The pilot project was launched during the fourth term of 2008 when 130 first-year B.Sc. students (of the four-year curriculum) did the practical component of the physics section of the Concepts in General Science (CGS) module by conducting experiments in a computerised laboratory, using data-logging software amongst other technology applications. “The pilot project delivered good results and students found the interactive application very helpful,” says Mr van Breda.

”The unique feature of the latter is the fact that real-life data can be collected with electronic sensors and instantly presented as computer graphs. It can then be analysed and interpreted immediately, thus more time can be devoted to actual Science principles and phenomena and less time on time-consuming data processing,” says Mr van Breda.

The CGS module can be seen as a prerequisite for further studies in physics at university level and in this regard it is of essence to keep looking for new models of learning and teaching which can result in student success. This year the theoretical and practical component of the physics section of the CGS programme will be done in an integrated manner.

Media Release
Issued by: Lacea Loader
Assistant Director: Media Liaison
Tel: 051 401 2584
Cell: 083 645 2454
E-mail: loaderl.stg@ufs.ac.za  
16 January 2009
 

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