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The Mercury Beating Heart
An
electro-chemical reaction creating a physical oscillation - this
is related to the BZ reaction - but more information about this later...
These are images from our first experiment recreating the Belousov-Zhabotinskii
reaction, which oscillates in both time and space, a so-called spatio-temporal
oscillator. It is a complex system involving bromate, bromide, malonic acid,
sulphuric acid, ferroin indicator, and oxygen. The oscillations in this reaction
start with the formation in a red solution of small blue dots that expand
in ever-widening concentric rings. ( Thanks to Nick Senior!)
See the photo stream
http://www.flickr.com/photos/antonyhall/sets/72157601563848492/
See the Film...
The main substances here are HBrO2 = Bromous Acid; Br-= Bromide ion; ferroin
and its oxidized form - Erin. This mixture we used was;
* Malonic Acid - 0.2 M/L
* Sodium Bromate - 0.3 M/L
* Sulfuric Acid - 0.3 M/L
* Ferroin - 0.005 M/L
The Belousov-Zhabotinsky reaction is a spatio-temporal chemical
oscillator. In 1951 the Russian scientist Boris P. Belousov discovered
that if
citric acid,
acidified bromate and a ceric salt were mixed together the resulting solution
oscillated periodically between yellow and clear. He had discovered a chemical
oscillator. The scientific community was united in believing this to be impossible.
Some years later another Russian biophysicist, Anatol M. Zhabotinsky "...
refined the reaction, discovering that when a thin, homogenous layer of the solution
is left undisturbed, fascinating geometric patterns such as concentric circles
and Archemedian spirals propagate across the medium..."(*see bellow)
Further
reading and Links:
An interesting paper that theorises that the waves, present in
both B-Z reactions and social amoebae life cycles, are analogous
to the waves of electrical activity
coursing through heart muscles...
" Similar Spiral Patterns have been observed in dishes of social amoebae
in a slime mould. Individual cells communicate in spiral waves at a certain stage
in their life cycles when they synthesise and hoard molecules of a hormone called
cAMP, to be suddenly released in an abrupt ‘sneeze’. Professor Winfree
suggests that this cAMP diffusion is perhaps in effect "a living fossil
replaying events that were common during evolution from unicellular to multicellular
organisms two billion years ago". The spirals rotate at about the same period
as the chemical wave in the B-Z reaction, with about the same speed and spacing.
The tiny rotating source at the core of a spiral
wave is called a ‘rotor’, and the term ‘pacemaker’refers
to the variably longer-period sources of concentric ring waves..."
http://people.musc.edu/~alievr/BZ/BZexplain.html
What the BZ reaction (BZR) is?
http://www3.baylor.edu/~John_M_Davis/bz/
An Analysis of the Belousov-Zhabotinskii Reaction
http://www.ux.his.no/~ruoff/BZ_Phenomenology.html
The Phenomenology of the Belousov-Zhabotinsky Reaction*http://www.hermetic.ch/pca/bz.htm
Computer simulations, which allow exploration of five different cellular
automata "All
of them use a 2-dimensional array of cells which can vary in size from 33x33
to 528x528. "Periodic boundary conditions" are used, meaning that
the left edge of the array wraps around to contact the right edge, and the
top edge
of the array wraps around to contact the bottom edge. The structure is thus
that of a torus, although it is easier to think of a 2-dimensional plane
in which
an unlimited number of copies of the square array are reproduced next to,
and above and below, each other (and each copy changes in the same way)."
