Most reactions proceed smoothly, at varying rates, to a final state of equilibrium. Some, however, do not. They oscillate in time: reactant, product, or intermediate species' concentrations which fluctuate wildly, often leading to easily observable oscillations because of these concentrations.

These reaction systems are of great interest. Many natural phenomena, from firefly flashes to your heartbeat, are oscillatory chemical systems, and spatial oscillations (tiger stripes, zebra stripes, and so on) are also familiar. While oscillating biological reactions are not completely understood, there are many oscillating reactions known among simple inorganic or organic molecules. Many years of research, both experimental and theoretical, have made clear the details of these reactions.

Initially, my intention in this project was to link oscillating reactions like the Belousof-Zabotinsky (BZ) reaction with circadian rhythms which we can all observe in live beings. To do so that I looked for information on the net and books, and I asked many professionals such as biologists, chemists, physics, nurses and doctors for any knowledge about this topic but I found nothing but suppositions. However I continued my project so as to try to understand those oscillating reactions and to promote their knowledge as much as possible since I think it could be possible that they were linked with life mechanism. In fact in BZ reaction are involved substances like malonic acid (which is an organic compound) and iron which is the key in the oxygen transport in hot-blooded live beings.

What I am going to explain in this document is a brief history of the discovery of chemical oscillating reactions, my little contribution to understand them better with the description of the experiments that I have done and some help to understand their mechanism through equations, graphics and the pertinent explanations.

I hope you enjoy this fascinating world of chemical clocks.

Xavier Vengohechea 28/01/04