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PERCOLATION DEFINITION

  • Examples of phase transitions in a single sample where the temperature changes:
    1. Melting of solid to liquid or freezing of liquid to solid
    2. Polymer transition - liquid to maadan desert
  • In one phase the particles move (liquid) in the other they remain connected (solid).
  • The PERCOLATION phase transition is between a phase where there is a connection throughout the system that passes e.g. electricity or a fluid and a phase where there is not (insulator or no fluid passage). Need a set of samples with different concentrations.
  • The connection can be conduction of current in a mixture of insulating and conducting spheres or passage of a fluid thru a system of pores, etc.
  • Look at the insulating (glass?) and metal ball mixture
  • At the percolation connection point - e.g. at the minimum number of conducting spheres that connect the system moves between a connected (ordered) phase to a disconnected (insulating) phase. THIS IS THE EXAMPLE at left.