# Last edited on 2017-02-07 05:16:30 by jstolfi

BUILDING A CELL TO MEASURE LIQUID RESISTIVITY

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2016-12-??

  Built a tentative cell to measure resistivity of liquids.
  
    Body: cylindrical PET bottle without the top part.
  
    Electrode 1: semicylindrical copper plate attached to the 
    inside wall of the body with silicone glue.
    
    Electrode 2: cylindrical copper tube section at center,
    held by two plastic spacers at top and bottom.
    
    Leads: solid insulated copper wire, soldered at the top of each
    electrode.
    
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2016-12-31

  Tried to measure the resistivity with a hand-held ohmeter.
  
    Water: 400 M Ohm
    
    Ethanol 46%:  230 M Ohm
    
    Ethanol 99%:  340 M Ohm
    
  Measurements were highly unstable, perhaps due to bad contact
  between meter probes and lead wires.  Also the copper electrodes
  had been brushed with a dremel brush wheel made of brass, which
  may have left residues.