October 2015
Contents / home
Global science engagement project
National Science Week activities
Science breaks barriers
Hydrogen fuel cell technology
Science that no classroom can teach
SAASTA empowers community
New CEO takes over reins at NRF
Hydrogen awareness website
Work shadowing at SAIAB
Field school for students
Meet Dr Zikhona Tetana
Improving technology education
Weather stations in schools
Street science
Space science appreciation
International Year of Light
Monitoring river health
Sasol Techno X prizes
In the news
Upcoming events
It's a fact!

SAAO celebrates the International Year of Light

The South African Astronomical Observatory (SAAO) collaborated with the South African Space Agency (SANSA) and the Light Research Institute (LRI) at Stellenbosch University to celebrate the International Year of Light in areas they would not normally visit, like Hermanus, Houston in the Overberg region, Saldanha Bay and Vredenburg on the West Coast.

The International Year of Light and Light-based Technologies aims to raise awareness of the achievements of light science and its applications, and its importance to humankind
SAAO outreach teams ran workshops at a range of schools on light and its uses, with particular focus on astronomy and laser

To bring the programme closer to home, a few public lectures were included in SAAO's usual programme on Saturdays.

Light and its role in science

A contingent of outreach teams ran workshops at a range of schools on light and its uses, with particular focus on astronomy and laser. The aim of these workshops was to emphasise the importance of light in sciences like astronomy – without light astronomers would be hard pressed to know of what chemical elements stars are made up, or the distance of objects, and the atmosphere of these celestial bodies would be a complete mystery too. Additionally, big scientific instruments use optical fibre to transport the light collected by telescopes to the instrument, and provide high-speed internet links to such instruments.

To demonstrate the many ways in which laser can be used for education and entertainment purposes, the learners bore witness to enthralling experiments on fibre optics used in communication. Music from an mp3 player was converted into light signals transmitted into a receiver to be decoded again – to explain how information can be decoded and transmitted into light. Fibre optics, also useful in astronomy, were used in this experiment and their function was explained to the learners.

In order to demonstrate that some fluids do not obey Newton mechanics, the learners were asked to think of materials readily available at home, like shampoo, a non-Newtonian liquid, by shining the laser through to showcase the internal reflection of light as it behaves in fibre optics. Another exciting demonstration was that of UV lamps and various dyes in solutions used to excite electrons in atoms, showing the excited energy in the form of light which results from that.

Messengers of a distant astronomical past

SAAO hosted two public lectures, one titled "Photons: messengers from the astronomical past" presented by Associate Professor Andreas Faltenbacher of Wits University. The lecture focused on photons and light particles, which travel for billions of years from the furthermost parts of the Universe until they hit the mirrors of our telescopes. They are messengers of a distant astronomical past, thus allowing us to gain an idea of the evolution of the Universe.

The second lecture was about the expansion of the Universe. PhD student Eli Kasai commenced his talk titled "Using light to prove that the Universe expands at an ever increasing rate" with the definition of light in technical terms and how we use it to measure distances by means of a physical law in physics called "inverse square law". He then proceeded to discuss the concept of standard candles, which are a class of astrophysical objects with known intrinsic brightnesses, and how we use them to precisely determine distances to objects in the Universe.

The talk ended with a discussion on how light from objects known as supernovae (exploding stars) was first used more than a decade ago to prove that the Universe has been expanding at an ever increasing rate, and how we use this same light to calculate how much mass and energy the Universe contains.

Staff writer, SAAO