History
The discovery of the phenomenon is credited to Boris Belousov. He noted, some time in the 1950s (various sources date ranges from 1951 to 1958), that in a mix of potassium bromate, cerium(IV) sulfate, propanedioic acid and citric acid in dilute sulfuric acid, the ratio of concentration of the cerium(IV) and cerium(III) ions oscillated, causing the colour of the solution to oscillate between a yellow solution and a colorless solution. This is due to the cerium(IV) ions being reduced by propanedioic acid to cerium(III) ions, which are then oxidized back to cerium(IV) ions by bromate(V) ions.
Belousov made two attempts to publish his finding, but was rejected on the grounds that he could not explain his results to the satisfaction of the editors of the journals to which he submitted his results. His work was finally published in a less respectable, non-reviewed journal.
Later, in 1961, a graduate student named Anatoly Zhabotinsky rediscovered this reaction sequence; however, the results of these men's work were still not widely disseminated, and were not known in the West until a conference in Prague in 1968.
There are a number of BZ cocktails available in the chemical literature and on the web. Ferroin, a complex of phenanthroline and iron is a common indicator. These reactions, if carried out in petri dishes, result in the formation first of colored spots. These spots grow into a series of expanding concentric rings or perhaps expanding spirals similar to the patterns generated by a cyclic cellular automaton. The colors disappear if the dishes are shaken, and then reappear. The waves continue until the reagents are consumed. The reaction can also be performed in a beaker using a magnetic stirrer.
Andrew Adamatzky, a computer scientist in the University of the West of England reported on liquid logic gates using the BZ reaction.
Strikingly similar oscillatory spiral patterns appear elsewhere in nature, at very different spatial and temporal scales, for example the growth pattern of Dictyostelium discoideum, a soil-dwelling amoeba colony. In the BZ reaction, the size of the interacting elements is molecular and the time scale of the reaction is minutes. In the case of the soil amoeba, the size of the elements is typical of single-celled organisms and the times involved are on the order of days to years.
Investigators are also exploring the creation of a "wet computer", using self-creating "cells" and other techniques to mimic certain properties of neurons.
Read more about this topic: Belousov–Zhabotinsky Reaction
Famous quotes containing the word history:
“Postmodernism is, almost by definition, a transitional cusp of social, cultural, economic and ideological history when modernism’s high-minded principles and preoccupations have ceased to function, but before they have been replaced with a totally new system of values. It represents a moment of suspension before the batteries are recharged for the new millennium, an acknowledgment that preceding the future is a strange and hybrid interregnum that might be called the last gasp of the past.”
—Gilbert Adair, British author, critic. Sunday Times: Books (London, April 21, 1991)
“The history of all hitherto existing society is the history of class struggles.”
—Karl Marx (1818–1883)
“American time has stretched around the world. It has become the dominant tempo of modern history, especially of the history of Europe.”
—Harold Rosenberg (1906–1978)