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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

Statement on protest at the UFS

2005-03-04

Following a protest by student and non-student organisations today, the management of the University of the Free State (UFS) would like to place the following facts on record:

1. There is a well-documented process underway to further transform the UFS. At the official opening of the UFS on 4 February 2005 , the Rector and Vice-chancellor, Prof Frederick Fourie, announced that the UFS would draft a comprehensive Transformation Plan to guide the next phase of transformation at the institution.

The UFS appeals to student formations, staff associations, trade unions and other role-players to make a constructive input into this Transformation Plan.

The UFS management has been - and always will be - willing to engage with role-players and is prepared to do so even after today’s protest.

2. There is thus no regulation or policy prescription which separates students in hostels according to race.

The reality is that students exercise their freedom of choice as to which hostel they wish to be placed in. This was agreed upon by black and white students in 1997/8.

However, the unintended consequence and practice of this hostel placement policy has been that students themselves have tended to choose to stay in hostels which have over time become black hostels and white hostels.

This is a matter of concern for the management of the UFS as such a situation does not promote interaction across language, cultural and socio-economic groupings of students.

This matter is receiving attention and an intensive consultative process, which will include students, will be launched to review this policy.

The management is convinced that such interaction will enhance the learning experience of all students and sensitise them to the reality of a multicultural South Africa and a multicultural world.

3. No student organisation has been banned from operating at any of the three campuses of the UFS.

In the past few weeks, SASCO, the Young Communist League and the ANC Youth League (ANCYL) have held meetings on all three campuses, namely the Qwaqwa campus, the Vista campus and the main campus.

There are also regular interactions between top management and the leadership of SASCO and the ANCYL on campus.

In fact, the UFS upholds the right of students and staff to associate freely and to organise themselves as they see fit.

The UFS also upholds the rights of staff and students to engage in legal and peaceful protests.

The management however remains committed to discussing issues that affect staff and students in a constructive manner and appeals to student organisations in this case to engage with management.

4. The issues of registration, fees, debt and financial aid are continually monitored, and interventions to assist students are made regularly. To assist as far as possible those academically deserving students who face financial difficulties, the UFS management has put in place a structure called the Monitoring committee that includes management and student representatives.

The purpose of the Monitoring Committee is to review the cases of individual students to determine how best they can be assisted.

This applies to the Qwaqwa campus, the Vista campus and the main campus.

It is generally the case that students who perform academically will not have any difficulty in obtaining financial assistance. However, according to the requirements of National Student Financial Scheme, students who perform poorly will have difficulty in obtaining such assistance.

5. With regard to student governance, the process to institute an inclusive Central Student Representative Council (SRC), on which all three campuses will be equitably represented, was launched in July 2004, and a preliminary constitution has just been drafted. At the same time an inclusive process to review certain elements of the constitution of the main campus SRC was initiated at the end of 2004. This process, which includes all relevant student organisations and structures, is planned to produce an outcome within the next couple of months.

6. There is no policy at the UFS that is based on racism or that discriminates on the basis of the race of students and staff.

As part of the building of a new institutional culture within the broader transformation process, the UFS management is determined to eradicate all elements of racism that may occur on its campuses, and has already instituted inclusive forums on campus to discuss the issue of values and principles for a non-racial university.

Issued by: Mr Anton Fisher
Director: Strategic Communication
Cell: 072 207 8334
Tel: (051) 401-2749
4 March 2005

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