News
British Science Week 2015
On Wednesday, 18th March, Bishop Challoner School celebrated the British Science Week 2015 with an evening class for Parents and Students. 11 families led by Dr Piccio and Dr Free took part in this series of demonstrations and practical activity based on Chemistry. This story was first told by Belousov and Zhabotinsky approximately 60 years ago. They had discovered oscillating reactions which are an important piece of evidence for the mathematical models developed by Lotka and Voltera at the beginning of the 20th century and for Turing’s models in early 1950. This research was a turning point in the quest to explain the formation of patterns in living organisms (flowers, animals, stripes, spots, fingers location...)
We started by looking at a common reaction, the combustion of ethanol in the whoosh bottle. We also looked at the combustion of chemicals that carry their own oxygen like gun-cotton. Both these reactions are extremely fast and finish dramatically. We then turned to lab-based reactions in conical flasks. The iodine clock reaction took 13 seconds to turn blue. The Briggs-Rauscher oscillating reaction appeared to return to its original condition, but, in fact was progressing slower than we are used to, making two steps forward one step back. Finally, students prepared an oscillating reaction and placed it in petri dishes. They observed the formation of circular patterns due to the different speeds of diffusion of chemicals in the dish. This is thought to be the model for explaining the formation of patterns in living organisms.